Refugiums don't export nutrients?

[FutureDoc]

btw, they (UMTAS) were adding 10µM of phosphate WOWZERS! ...that is 5-10X seawater is 0.86 to 1.98 µM for phosphate in deepwater, coastal Japan (trying to get away from overly terrestrial contamination...and avoid abyssal influences).

 

phosphate concentration in seawater (deepwater, nearcoastal Japan): It was quick and easy so sue me... folks want direct links.

http://svr4.terrapub.co.jp/journals/JO/pdf/5605/56050553.pdf

[FutureDoc]

Let us see if we can actually have you catch the logic train this time...

 

A eutrophic species, Ulva, that grows with excess nutrients and its growth is an indicator of high nutrients whether the nutrient are in the watercolumn or are benthic in origin. Ulva is an common estuary species.. I do not see how it helps a reef-crest stony environment.

 

Seriously, think hard. How can organism growth to be an effective limiter of the nutrients when that limit is dependent on the organisms growth.... see the issue? You like to call me circular but... dang. That is as circular as you get in a logical fallacy. Either you reach a point of stasis (where algae is growing good to match imput but for algae to do this,there must be plenty of nutrient sunk into the system). Why don't you also post that you are going to deplete the Ca demand in your tank by SPS growth.

 

You can not prove that you have low phosphates in the system if you have growing healthy algae in the system. And I say system. Rock, sand, bacteria, etc. It if is excreting, and everything alive excretes, it is processing (incorporating and releasing) P. If P were limiting, the algae would not grow. Thus, no nutrients, no algae. No one is doubting that removing algae will result in a net loss of N and P.... but growing algae means there is a net gain in N and P. Considering you are not removing 100% of the algae mass nor are you able to reduce/roll back the process of eutrophication. You can not make an environment that is conducive to algae growth for nutrient export the environment low nutrient environment preferred by stony reef corals.

 

I am waiting for the magical card game too, it seems to be a myth you created... Is it like the one where the algae holds the P until the hobbyist removes it? That is a great illusion.

 

I know what a oligotrophic system is, I know what a euthrophic system is, I know what happen when you add hyper before those terms and I know what a mesotrophic system entails. You say I am blind by my "ULNS", but I am just playing within the bounds of ecological understanding, definitions, and frameworks. So much for being "blind".

[chrisK]

Let us see if we can actually have you catch the logic train this time...

 

A eutrophic species, Ulva, that grows with excess nutrients and its growth is an indicator of high nutrients whether the nutrient are in the watercolumn or are benthic in origin. Ulva is an common estuary species.. I do not see how it helps a reef-crest stony environment.

 

Seriously, think hard. How can organism growth to be an effective limiter of the nutrients when that limit is dependent on the organisms growth.... see the issue? You like to call me circular but... dang. That is as circular as you get in a logical fallacy. Either you reach a point of stasis (where algae is growing good to match imput but for algae to do this,there must be plenty of nutrient sunk into the system). Why don't you also post that you are going to deplete the Ca demand in your tank by SPS growth.

 

You can not prove that you have low phosphates in the system if you have growing healthy algae in the system. And I say system. Rock, sand, bacteria, etc. It if is excreting, and everything alive excretes, it is processing (incorporating and releasing) P. If P were limiting, the algae would not grow. Thus, no nutrients, no algae. No one is doubting that removing algae will result in a net loss of N and P.... but growing algae means there is a net gain in N and P. Considering you are not removing 100% of the algae mass nor are you able to reduce/roll back the process of eutrophication. You can not make an environment that is conducive to algae growth for nutrient export the environment low nutrient environment preferred by stony reef corals.

 

I am waiting for the magical card game too, it seems to be a myth you created... Is it like the one where the algae holds the P until the hobbyist removes it? That is a great illusion.

 

I know what a oligotrophic system is, I know what a euthrophic system is, I know what happen when you add hyper before those terms and I know what a mesotrophic system entails. You say I am blind by my "ULNS", but I am just playing within the bounds of ecological understanding, definitions, and frameworks. So much for being "blind".

 

In our closed system you will always have nutrients in our tank. Unless you have a continual source of *fresh* saltwater flowing into your tank.

 

I agree with you in that algae can be a good indicator that you have a phosphate problem in your tank, and by growing macro algae in a refugium, is a very contradictory theory in trying to fix the problem with a problem.

 

But would you not be able to grow macro algae even in a ULN system?

[xerophyte_nyc]

It's fun to debate this back and forth, but we are all missing a critical point here. Practically none of the literature cited in this thread offers anything more than proof of concept. I have a 39G cube in my living room, not the Great Barrier Reef. What happens in the ocean, estuary or lagoon environment does not translate directly into our hobby. If anyone here was seeking drug approval through the FDA, at best we would be at Phase 1.

 

Until we have repeatable evidence in an aquarium, we are all just a bunch of blowhards.

 

My tank does not have herbivores other than me when I prune. My tank does not have continuous introduction of new water like a tidal lagoon. My tank has species from different oceans. I don't feed continuously like an ocean does. I don't have a thriving phytoplankton population that makes up the majority of the biomass. I don't have real sun.

 

It doesn't matter that research proves that algae = eutrophy in an ocean. All that proves is that algae grow better than coral when nutrients are high. That's it. The rest is conjecture with so many variables that it is almost impossible to make it anything else.

 

The only value that proof of concept has is that you can use that info to control your environment. We know that coral need calcium, so we can dose calcium to our benefit. We know that algae sucks up nutrients, so we use that to our benefit. If there are no nutrients, then algae won't grow. We also know that it is practically impossible to create a low nutrient aquarium resembling the ocean. That doesn't mean it is a bad thing. It just means we can't do it effectively.

 

The second after food is added to an aquarium it is no longer ULNS, compared to a reef. Instead of moving heaven and earth (and water change ) to make ULNS reality, it is more practical to try and export nutrients using all means available to us. I use algae because I feed alot.

 

I am like a school of tang, plucking away at algae on a reef. Herbivory is missing in my system, so I have to eat my algae. The circle of life!

[albertthiel]

There are many benefits of refugiums, but it has to be planned out and used properly for it to really make a dent in nutrient levels. Nutrient export is rather low unless your refugium is large, exceptionally well-lit, and trimmed often before any macroalgaes die off. One benefit that far outweighs that, though, is that it is a safe haven for copepods and other beneficial critters, and by that alone I think everyone should have one.

 

Do I think refugiums cause cyano? Absolutely not, unless it contains some sort of fancy 'miracle mud' (as in, it's a miracle if this stuff does anything) or the like that is not seeded thoroughly and consistently with microfauna that make a sandbed truly 'live', otherwise the bed will simply become a nutrient sink.

 

+1 maintenance of a fuge is just as needed as it is in the DT as you state Ben +1

[Griever]

I think one of the key leaps of logic that future doc is missing is that in our refugiums, the algae is being removed. In all of the studies I looked at, the algae is being left alone. It makes sense that if it's left alone, it'll die back and grow in response to fluctuating nutrient levels, and cause cycles of high and low P. That's not really applicable to what we're doing though, is it?

 

When we are removing the new growth regularly, we're exporting that out of the system. I don't see how you can argue that it's not a net export. The Algae doesn't take light and water and produce P, so it's all stuff that's already in the system from what you'd normally feed.

[xerophyte_nyc]

(yup, finally got access to it and its not surprising that you won't post for it, since it doesn't make the claims that you say it does)

 

Any chance you can share it?

[FutureDoc]

Algae is being removed and I have stated that is a net loss (said it several times) but it ignores the fact that to have that net loss, you must allow bacteria to process organic P (as well as other organic materials) in order to generate that net loss. One must look at it some a systems concept. Sure, a net loss is great, but the other issue is that you are leaving a lot of algae in the tank (different from a ATS but we can get to that later). You are leaving the co-dependent bacterial within the system. You have organic P moving back into the system from the un-harvested algae, dying algae, dying bacteria, on top additional feedings. You also have the Ca-based rock taking a cut. So it becomes an issue of where you want to address the underlying issue of nutrient gain and mask it with algae or address the root cause (ie bacteria consuming organic matter where the P is bound and unavailable to algae). You can either make this circle large loop with algae or you can disrupt the P cycle as much as you can.

 

If you want to just polish out a little "leftover" inorganic P, then use GFO because at least it can polish, does not re-release P, and does not require significant P to become available in order just to remain in stasis.

 

My logic is simple, disrupt the P cycle as much as one can, rely on WC to bat "clean-up" for any leftover Pi or let the skimmer cat the phyto population as best it can. Do not all P to make it to the mass algae consumption level. P is not stationary in algae, it is not locked, and like any organisms, it "poos", gains, mass, dies, etc. Increasing the biomass of a non-display organism is useless bio-mass increase.

 

I hear about that a "properly maintained refugium", but let us define that a bit more then. I heard the same things about a properly maintain DSB too.

 

Please quote to whereby that article disproves my point?

[brandon429]

I do not see the bacteria left in the system, that were boosted by the extra nutrients as well as the attachment substrate from the algae, as bad. When we feed tanks, there is a large boost in populations for the same reasons, the food is both attachment substrate and food.

Then the DOM matter spreads around the tank to boost populations temporarily on all surfaces, in fact feeding the tank would be a worse cause of bbloom. how was the ats different than the macro algae solution if both are being pruned doc? I see bacteria as nothing to be concerned about in our tanks....just that w regular care those populations will self regulate.

 

Now Im a big water changer anyway, moreso than any tank on this site so that may already play in to the care methods you guys are talking about, it was coincidental that I already export both species of phosphate without concern, so I never have to test for anything including major ion components of the water. We have found that for the common bioloading and feeding for small pico reefs, weekly rip changes of all the water fixes everything. Interestingly, when they age, its not enough to just change all water, very small pico reefs have to be dosed with ca and alk and its interesting to see what you wrote that may be commanding it.

 

I could tell it wasnt just coral growth, without the dosing algae really starts to take over. I have known and advised for years that to keep really small picos alive for decades potentially, you have to dose or change all water every day which no one wants to do. none of this happens in the first two years, its after that where the small systems get really ion hungry and I wasnt exactly sure why. It remains an undiputed fact that two part dosing, or however you want to maintain calcium and alk dosing, directly fights algae battles in the small pico reef. You can get by without dosing, but its more work for the tank.

 

I strongly feel that the flash binding of phosphate from the calcium component really helps in the small body of water

[xerophyte_nyc]

My logic is simple, disrupt the P cycle as much as one can, rely on WC to bat "clean-up" for any leftover Pi or let the skimmer cat the phyto population as best it can.

 

We all agree about this part. But despite our best efforts there will still be leftover Po. Since there is no efficient way to get it all out, we are left with exporting the resulting Pi. WC will do it, as will GFO, as will algae. If your husbandry is so good that there is little Pi remaining, then you won't need much algae or GFO at all. But some of us like to "feed the reef", which leaves us with more Po than we can handle without enlisting the help of something like algae.

[FutureDoc]

So where does that algae-removal method address bacteria removal. Which is bio-bacteria removal important?

 

 

From D. Currie and J. Kalff (1984, p. 308) Limnology and Oceanography , Vol. 29, No. 2 (Mar., 1984), pp. 298-310

 

 

"In view of these results and other published studies, we propose a qualitative model of algal-bacterial interactions as follows. Bacterioplankton are limited by the supply of reduced carbon, which they obtain to a large extent from algal excretion (Williams 1981; Jones et al. 1983). Bacterioplankton growth and abundance are thereby positively related to algal abundance and activity. Bacteria utilize phosphorus as a positive function of the supply of organic carbon. Algal growth, ordinarily phosphorus-limited, depends inversely on bacterial phosphorus utilization and growth. We envision phytoplankton and bacterioplankton dynamics as being tightly coupled: both should respond in a similar fashion to trophic variations"

following up on "excretion" along with bacteria... Lemasson and Pages (1980) Estuarine, Coastal and Shelf Science

"The two types of evaluation of the excretion are very different since in the first case tracer is in the medium, and in the second case it is the microbial biomass which is labelled. In addition excretion is proceeding from organisms for which radioactive P-uptake is stopped through lack of a2p-PO 4 in the substrate... we can compare phytoplankton P-excretion rate to PO4-P uptake rate, and get tile P-excretion rate relative to microbial biomass which is evaluated by particulate phosphorus (Pp). Pv is a good evaluation of biomass because detrital Pp is low (Lemasson et al., 1980b )... (p. 514)

Nonetheless it has been shown that the inverse effect can occur; Kuenzler (1970) observed anomalously high excretion during low growth, but on pure cultures, and for certain cultures Watt & Hayes (1963) observed that DOP originates from dead organisms. Organic excretion seems then to be related to the physiological condition of cells. (p.520)

[Later on]

In the case of the populations studied here, the excreted DOP represents at least 8% of gross P-uptake. This is not negligible and would justify a closer study. We can imagine two ways of excretion; the first would correspond to the physiological condition of the cell, and involve a compartment readily exchangeable with around 28% of the biomass, while the second would involve a compartment more closely linked to internal metabolism. " (p. 521) [please note that the rate is liked to metabolism... thus my "it depends" answers".

Where it is as long as 8% or towards 28%, this is the major flaw with algae. It misses P. It puts come P "back" into the loop. As biomass increases, it puts more back, both in total mass as well as in a % of biomass. It is that inefficiency that dooms the method. It is not a linear progression where P is locked into algae mass. Algaeharvesters ignore bacteria, ignores the loss of P as proportional to nutrient availability and biomass.

Algae removal is kinda like keeping your water at 100ppm nitrate so that with each 20% you can remove 20ppm nitrate from the water... and then say, look at all the nitrate removal. On the other hand, you could just remove the N particles before they become prevalent. It does not matter if you are removing less total mass if the total mass is less to begin with.

[xerophyte_nyc]

how was the ats different than the macro algae solution if both are being pruned doc?

 

The only difference really is that the algae in an ATS have greater flow and better lighting, so photosynthesis is more efficient thereby growth and nutrient uptake can potentially be MUCH better than macro in a tank.

[FutureDoc]

We all agree about this part. But despite our best efforts there will still be leftover Po. Since there is no efficient way to get it all out, we are left with exporting the resulting Pi. WC will do it, as will GFO, as will algae. If your husbandry is so good that there is little Pi remaining, then you won't need much algae or GFO at all. But some of us like to "feed the reef", which leaves us with more Po than we can handle without enlisting the help of something like algae.

 

 

If there are leftovers, then increase the WC/siphoning routine. Seriously. Match the bioload demands with the water/detritus export rather than rely on algae (which does it own thing) and give a false negative. It is more than possible to achieve the low P system and GFO can be removed or kept on depending if folks like it although the effects of iron/GFO might be suspect on coral health (different can of worms and I personally think as long as GFO is not overdone (don't add a pound to a 5 gallon tank, it is fine).

[brandon429]

The only difference really is that the algae in an ATS have greater flow and better lighting, so photosynthesis is more efficient thereby growth and nutrient uptake can potentially be MUCH better than macro in a tank.

 

another thing I like about ats is you are letting naturally selected mats form from aerial and water born growth potentiators form that have chosen to be in the tank with all its variables. vs putting in and "trying" something which may have different growth rates

 

what shows up in an ats wants to be there, and is hungry, all the time.

[FutureDoc]

The only difference really is that the algae in an ATS have greater flow and better lighting, so photosynthesis is more efficient thereby growth and nutrient uptake can potentially be MUCH better than macro in a tank.

 

The biomass being exported.... ATS subscribers tend to set biomass removal % much higher than macro-cultivators. In addition, you are dealing with much more aggressive algae-types as the "turf" algae is much more opportunistic than chaeto or caulerpa.

 

They are good for their aggressiveness, but that also hints at the nutrient status of the tank. So aggressive turf algae growth is inductive of higher nutrient availability. In higher nutrient availability, turf algae shed more organics (P) back into the water column. In addition, if ATS begin to reach their nutrient limits, they themselves are much quicker at culling their populations, so if you are not removing at the point just before limitation occurs, then you miss the peak harvest and run the risk of algae releasing ample nutrients back into the water in order boost bacterial activity. So, with ATS, you are either left at harvesting too frequently and not achieving a nutrient limiting status, or harvesting no frequently enough to prevent die-back. It is kinda like auto-racing with a manual, shift to early and you lose the powerband at higher revs (ie you slow) or shift to late, hit the rev limiter, and lose power as well. But algae does not give folks a tachometer. If ATS had a very clear "remove me now, I am optimal" sign, it would have more traction but otherwise it is a guessing game and that really hurts the method.

 

Oh, and did I mention that turf algae are adapt at trapping detritus? So it kinda acts like a dirty canister filter that gets light.

[brandon429]

regardless of the predicted mechanics, there are thousands of examples of pre and post ats tanks. The post tanks have less DT algae, hence the myriad people using it. Ive read of people being meticulous cleaners before the ats, and still getting algae, but afterwards their work load was lessened so they kept it using whatever pruning cycles they were doing.

[Reefin Dude]

Hmmm...not so sure about this. In my tank, albeit in a very limited time frame, my ATS has provided steady growth and harvest, while the presence of algae in the display tank has slowly been visibly reduced. There was also a handful of macro I had in my sump day one which grew quickly as the tank cycled and had minimal nutrient processing. But that macro too has noticeably receded. There is a finite amount of P, and it seems to be favorably assimilating into the ATS (and adsorbed into the substrate). If it was accumulating, I would expect to have visible evidence - nuisance algae. Or it could all be adsorbing into the sand.

 

it is being absorbed in the various phosphate sinks. the calcium carbonate based substrate being the biggest. having two entities fighting for every atom of phosphorous in the same spot can allow for a lot of temporarily locked up phosphates. both organically bound and free Pi. nothing wrong with this as long as one knows it is happening. the ATS is also acting like a phosphate sink, but it is a lot more temporary than the substrate. being a living organism it is constantly trading phosphates for energy along with binding some for building blocks. at any point it time any of those phosphates could be released or converted then released back into the system for use by other organisms. in the substrate they are pretty locked up until there is not room, or the substrate is stirred up either on purpose or an unfortunate power head calamity.

 

 

Personally, I do not subscribe to the idea that when the substrate has a 'bloom' of some sort, the substrate needs replacing. In nearly 5 years working with my Nano, I have found that the blooms are caused by excess nutrients in the detritus in the SB. I caused this condition myself initially with too much feeding/too little detritus export, then stirring up the SB after having left it undisturbed for too long. Once the nutrients are removed via vacuuming and WCs, however, the blooms inevitably disappear. What phosphate might leach from the substrate due to biological processes (if any) is not measurable.

 

I still use the same 1" depth aragonite substrate I started with (with maybe an additional half-cup added due to dissolution) and, even though it has had ample opportunity to bind Phosphates, there are no blooms as long as I remove the detritus regularly. The tank also has had consistent '0' inorganic phosphate (Salifert) for the years I've been regularly vacuuming and little micro or macro algae. And most importantly, the mixed corals are healthy, growing and colorful.

 

On a side note: I must point out that in scientific field studies, when a portion of a healthy reef is netted off to prevent herbivores from accessing the area, macro algae will grow and eventually out compete the corals. Obviously, algae can grow in very nutrient depleted water and herbivory is the main means of control.

 

Personally, I would consider using Macroalgae as a nutrient export tool (as well as a means of reducing nuisance algae in the display tank) if I had a large enough bio-load.

 

i am lost on how your experience is counter to what i was saying about how substrates work and their is a slow migration of phosphates downward through the substrate. if this is not occurring then why is the detritus in the substrate instead of always on top? if the detritus was always on top, then why would stirring a substrate or a powerhead stirring the substrate create such a influx of nutrients into a system causing problems? the nutrients either work up, or work down. you can not have both. i put my money on downward.

 

after you clean the substrate you have opened up new binding sites in the calcium carbonate allowing more phosphates to bind to it and the process begins again. the more you siphon the more binding sites that can be opened up by bacteria. they are also getting a new source of carbon from the mixing of the substrate from cleaning.

 

Do you mean LR purges itself of detritus, or of weakly bound P?

 

yes. this is what curing/cooking/purging LR is all about. using the bacteria to free the phosphates from the matrix (life would not exist on earth if this was not possible BTW). the bacterial mass of this pushes other bacteria out of the way causing a bacterial migration/bacterial pressure. at one point this term was called turgor, but not sure what people want to call it now. over time this pressure brings this bacterial flock and other loose material to the outsides of the LR where flow can then sweep it away. this is why when you put LR in a clean dark bucket of warm SW you will soon find detritus at the bottom of the bucket. this can be done even with dry LR and a few ml of ammonia to get things started. the phosphates are there. life on earth depends on some phosphates being there.

 

Still, no data to back up these sweeping, inaccurate statements.

 

I've also yet to see anything linked that even remotely indicates that adding algae to a refugium "pushes the system towards nutrient enrichment". I've yet to see anyone (other than our NR friend kgoldy, who might) suggest that you don't have to siphon, skim or change the water if you have a few macros in there.

 

Honestly, I'd really love to read your study showing that adding macros creates a nutrient rich environment, but so far it has been elusive . The circular argument where you make claims without any supporting documentation continues...

 

nobody is saying that algae is pushing the system towards a nutrient enrichment. it is proving that it is already there. it is a biomarker that nutrient are high enough to grow algae. a google search on the terms coral reef and eutrophication will bing up a gold mine of information about this.

 

According to their documentation on the product:

 

"The role that microbes play in a zeolite filtration method is extremely important: they

convert nutrients existing in excessive concentrations into biomass, which is then (in

the case of planktonic bacteria, or “bacterioplanktonâ€) consumed by corals and other

suspension-feeding organisms and utilized in biological processes, and/or removed

from the aquarium by protein skimming. The process may be thought of as nutrient

recycling and export, and in that regard it provides some of the same benefits that a

refugium housing macroalgae provides"

 

and what is feeding all of those microbes? how does all of this material get out of the zeolite? are there magic organisms that hang their butt end out of the substrate to poo? do all of these organisms leave the zeolite when they know they are going to die to make sure their bodies do not decay in the substrate? again this is hobby literature where they focus on the water parameters and not on the system as a whole. they are ignoring all of nutrients that are temporarily bound within all of this biomass.

 

So everyone with a substrate in a reef tank is using GFO (I am not however...), and when they do, they must constantly increase the amount used? You should be more thoughtful of broad, sweeping statements...

 

This is then coupled with the doozy of "reef-specific" salts being high in Ca and Alk due to the need to fight the effects of bacterial growth - of course assuming one has enough wastes to feed said bacteria, right? That and it is not there for coral growth at all, correct?

 

Wow...........

 

Seriously, I can't take any more!

 

did i say every system? who is making broad statements? i would however ask you to look through the forums and notice how often GFO and refugiums come up in the same thread, and how often both are recommended for the same purpose. just saying.

 

do you even know what is limiting for coral growth? it is not Ca. we can get into this now if you would like. you all have been ignoring the references to phosphates clogging up the calcium pump in hermatypic organisms, i figure you all were researching before asking questions. hint. the skeleton is just a turd.

 

That's the problem with aquaria - nutrients will always be there unless you starve the tank. Minimal feeding is not necessarily a bad thing, depends on what you want to accomplish with your tank.

 

ULNS + ample feeding probably cannot coexist in a reef tank. We stock way too high to be able to resemble anything close to a real reef. Trying to attain an ULNS filled with SPS does not seem attainable without food restriction. Maybe coral growth/ health is less than ideal as a result? Maybe a dirty, well fed tank that can export efficiently can support great SPS growth?

 

again. if one wants to keep an oligotrophic environment for SPS, then design the system for detrital removal as its primary goal. it can be done, and done easily. no need for food restrictions if the wastes and leftovers are removed in a timely manner. the current thinking in reefkeeping is all about keeping poo as a pet. everything from the fact that the sizes of skimmers are way to small, they do not process enough water to really make a difference. the current reef design thinking is about perfect for maintaining slightly eutrophic systems. if i wanted to keep a softie tank, then i would follow all of your advice. the fact is that we can not use a single design for all trophic levels that one would like to emulate. the reason why it seems like the current thinking works is because it relies on the great phosphate sink known as the substrate. it is doing all of our phosphate heavy lifting allowing the hobbyist to fine tune using other phosphate binders. the fact is still the vast majority of the phosphate are not leaving the system, but are just lurking in the substrate.

 

To repeat, the gist of why macro-algae do not represent an ULNS, is that the mere ability to grow algae, by definition, precludes a low nutrient system - because if nutrients were indeed low, there wouldn't be algae. Therefore, utilizing the same said algae for nutrient export cannot effectively reverse the tank's course back to a low nutrient situation, because then there would be no algae to get you to that point.

 

How about this as a corollary:

 

If you successfully employ various strategies to attain an ULNS aquarium, for ex. skimming, siphoning and water changes, AND your tank does NOT support macroalgal growth, then you are not feeding enough for optimal SPS coral growth and health.

 

don't confuse Po with Pi. do we really want our corals feeding on poo? if we feed less, in order for the corals to get enough food, they must be relying on waste products to provide the food they need. yes, they can eat some bacteria and other "plankton" but is that really what they need. design the system around detrital removal, then feed what the animals in our tanks want, and not on leftovers or other waste products. in this study there is an interesting observation that i think needs a lot more research on. i have not found any other references to support or deny this, but i have have also read this from Bomber/Spanky. that the majority of reef feeding occurs on the incoming tide and not the outgoing tide. this is huge if this is the case. the incoming tide would be full of Po in the form of plankton, the outgoing tide is full of Pi from land runoff, this makes a ton of sense and unfortunately goes against everything we have been taught by the "sand experts".

 

"Fish were always most abundant on the incurrent side of the reef and within an archway during the day. "

 

if this is true, then why would it not also be true for corals?

 

It's fun to debate this back and forth, but we are all missing a critical point here. Practically none of the literature cited in this thread offers anything more than proof of concept. I have a 39G cube in my living room, not the Great Barrier Reef. What happens in the ocean, estuary or lagoon environment does not translate directly into our hobby. If anyone here was seeking drug approval through the FDA, at best we would be at Phase 1.

 

Until we have repeatable evidence in an aquarium, we are all just a bunch of blowhards.

 

My tank does not have herbivores other than me when I prune. My tank does not have continuous introduction of new water like a tidal lagoon. My tank has species from different oceans. I don't feed continuously like an ocean does. I don't have a thriving phytoplankton population that makes up the majority of the biomass. I don't have real sun.

 

It doesn't matter that research proves that algae = eutrophy in an ocean. All that proves is that algae grow better than coral when nutrients are high. That's it. The rest is conjecture with so many variables that it is almost impossible to make it anything else.

 

The only value that proof of concept has is that you can use that info to control your environment. We know that coral need calcium, so we can dose calcium to our benefit. We know that algae sucks up nutrients, so we use that to our benefit. If there are no nutrients, then algae won't grow. We also know that it is practically impossible to create a low nutrient aquarium resembling the ocean. That doesn't mean it is a bad thing. It just means we can't do it effectively.

 

The second after food is added to an aquarium it is no longer ULNS, compared to a reef. Instead of moving heaven and earth (and water change ) to make ULNS reality, it is more practical to try and export nutrients using all means available to us. I use algae because I feed alot.

 

I am like a school of tang, plucking away at algae on a reef. Herbivory is missing in my system, so I have to eat my algae. The circle of life!

 

again, design the system around detrital removal as its primary mission if an oligotrophic system is desired. all we hear is that it can not be done, but why? stop thinking inside the box. think about what can be done to remove detritus, or keep it from rotting as fast as it can. what happens if instead of processing 2-3x of display volume through a skimmer, you process 10X. what if one collects detritus in a device that is tall instead of wide? wouldn't that cause decay to slow because of a lack of O2?

 

G~

[FutureDoc]

And there are a lot of examples of ATS tanks being rather unsuccessful in keeping story corals over time. A lot of folks though Acros were "impossible" for a long time which happened to correspond with wide-scale application of Adey's methods. It was not until non-algae based berlin methods came about did that change... and then the DSB craze hit. Uggg.

 

ATS has a lot of applications, but not really as something we want in a tank focusing on calcifying corals. Softie, nutrient-loving corals, algae can be good for them (or at least co-exist in the nutrient loading of the tank).

[xerophyte_nyc]

From D. Currie and J. Kalff (1984, p. 308) Limnology and Oceanography , Vol. 29, No. 2 (Mar., 1984), pp. 298-310

 

In a previous post you scoffed at providing literature from 2000, but here the lit is from 1984??

 

 

"In view of these results and other published studies, we propose a qualitative model of algal-bacterial interactions as follows. Bacterioplankton are limited by the supply of reduced carbon, which they obtain to a large extent from algal excretion (Williams 1981; Jones et al. 1983). Bacterioplankton growth and abundance are thereby positively related to algal abundance and activity. Bacteria utilize phosphorus as a positive function of the supply of organic carbon. Algal growth, ordinarily phosphorus-limited, depends inversely on bacterial phosphorus utilization and growth. We envision phytoplankton and bacterioplankton dynamics as being tightly coupled: both should respond in a similar fashion to trophic variations"

following up on "excretion" along with bacteria... Lemasson and Pages (1980) Estuarine, Coastal and Shelf Science

When I last checked, I do not (and neither does anyone else) have a thriving phytoplankton population in our tanks. If we are to take a leap of faith that phyto = macro, then we need some evidence that the 2 can operate under similar biodynamics, in an aquarium.

I also have some serious doubts about your ability to interpret the lit and the M&M based on earlier papers you referenced.

 

Where it is as long as 8% or towards 28%, this is the major flaw with algae. It misses P. It puts come P "back" into the loop. As biomass increases, it puts more back, both in total mass as well as in a % of biomass. It is that inefficiency that dooms the method.

You know what I'm going to do? I am going to take my next harvest of algae from my ATS, give it ample time to dry, and then weigh it. I will guesstimate the weight of phosphorus (which is 1-3% based on lit), and then extrapolate those numbers to guesstimate the equivalent in dry food weight, and see how that compares to what I actually feed. Can't argue with that.

 

It is not a linear progression where P is locked into algae mass. Algaeharvesters ignore bacteria, ignores the loss of P as proportional to nutrient availability and biomass.

Sure it is linear. It may not be terribly efficient, but it's not like algae is creating new P out of atomic matter. There is net P being exported when algae is pruned. Just because those P molecules may have been part of bacterial ATP the day before, or part of the shed chitin from an amphipod that molted last year, doesn't mean the net result is not linear.

What we need to substantiate is whether this net export is equal or greater than net import. It seems that you are trying to demonstrate that net P export is less than import. Correct? That would indeed be very bad. Even worse if it is very slow because then there are no good signs/ symptoms of future doom.

What is the time interval used in the study to measure the 8-28% shedding of algal Po? If that is something happening daily then algal pruning would have to be done every few days to approach anything close to acceptable. But if that is a week's worth of Po leakage, then it is favorable.

[xerophyte_nyc]

in the substrate they are pretty locked up until there is not room, or the substrate is stirred up either on purpose or an unfortunate power head calamity.

 

Between all the other info being thrown around back and forth on this thread, I come back to the idea of the substrate acting as a sink as the most important take home message.

 

That will likely be the only thing I will address in my own aquarium. I will probably do something like scoop out the top 1 or so inches of about 20% of my substrate, and every other month do the same for a different section, and the net result is 100% turnover of substrate bound P every year or so.

[xerophyte_nyc]

And there are a lot of examples of ATS tanks being rather unsuccessful in keeping story corals over time.

 

Are these examples from people who rely on an ATS? I know there are reefers who only use an ATS and don't ever do WC, etc.

[FutureDoc]

 

In a previous post you scoffed at providing literature from 2000, but here the lit is from 1984??

 

When I last checked, I do not (and neither does anyone else) have a thriving phytoplankton population in our tanks. If we are to take a leap of faith that phyto = macro, then we need some evidence that the 2 can operate under similar biodynamics, in an aquarium.

I also have some serious doubts about your ability to interpret the lit and the M&M based on earlier papers you referenced.

You know what I'm going to do? I am going to take my next harvest of algae from my ATS, give it ample time to dry, and then weigh it. I will guesstimate the weight of phosphorus (which is 1-3% based on lit), and then extrapolate those numbers to guesstimate the equivalent in dry food weight, and see how that compares to what I actually feed. Can't argue with that.

Sure it is linear. It may not be terribly efficient, but it's not like algae is creating new P out of atomic matter. There is net P being exported when algae is pruned. Just because those P molecules may have been part of bacterial ATP the day before, or part of the shed chitin from an amphipod that molted last year, doesn't mean the net result is not linear.

What we need to substantiate is whether this net export is equal or greater than net import. It seems that you are trying to demonstrate that net P export is less than import. Correct? That would indeed be very bad. Even worse if it is very slow because then there are no good signs/ symptoms of future doom.

What is the time interval used in the study to measure the 8-28% shedding of algal Po? If that is something happening daily then algal pruning would have to be done every few days to approach anything close to acceptable. But if that is a week's worth of Po leakage, then it is favorable.

 

I scoffed at non-peer reviewed trade literature conducted by those with a vested commercial interest for particular methods... not the date.

 

You have a thriving phytoplankton in your tank. It is just not the the point of eutrophic "green water" .... hopefully. Plus phyto is potentially skimmable. So there is the Pi export. Benthic or even free-floating macro algae is much less competitive but it still conducts the exact same basic processes at the cellular level. Calvin cycle and Photosynthsis are basically the same.

 

If you want to get into research design, sure. What is the hyposthesis (and really, what is your null?), how many trials before we we reach Stat. significange, are we controlling for nutrients already in the system, are we controlling for skimmate removal (ofte sigificant P removal) are we controlling gor algae type (as one of those articles suggest that P content varies on type, location, and trophic status), are we controlling for bacterial, pods, benthic inverts, and fish biomass increase? The problem of your proposed study is that I am extremely certain that you can not actually control to achieve a specific result without possibly having internal or external validity issues or attributing a spurious relationship in at least one assertion. Finally, I think you would goof and the whole collilation vs causation issues and completely forget to test for independence first.

 

Yep, I think you just proved the first "linear" cycle. If it was linear, then life would have ended on earth along time ago as all P would be exhaused.

 

Net P export is not the important part. Exporting 1 gram of P in a system that has 100g of P bound within the biota is much less significant that 0.1g if the system has 1g of P. See the issue? When dealing with Liebig's law of the minimum, if you are removing the part of the excess, you really are not doing anything because it is not limited. Take away a small amount near the limit, there there can be a big shift, and keeping below is the limit even with small reductions is still significant. I can give a "fat person and diet exmaple" but I think the lesson would be wasted.

[FutureDoc]

Are these examples from people who rely on an ATS? I know there are reefers who only use an ATS and don't ever do WC, etc.

 

And why is that If we remove all the other variables, what happens with ATS and our tanks? What happened with Adey. What happened with the Smithsonian system? Why do many folk's skimmer respond (more, thick darker skimmate) after the addition of an ATS? Follow the biological processes and the ecology.

[xerophyte_nyc]

The problem of your proposed study is that I am extremely certain that you can not actually control to achieve a specific result without possibly having internal or external validity issues or attributing a spurious relationship in at least one assertion.

 

My "proposed study" is completely unscientific, I will be the first one to admit it. It's just for my own curiosity. It can give me a reference, that is all.

 

 

Net P export is not the important part. Exporting 1 gram of P in a system that has 100g of P bound within the biota is much less significant that 0.1g if the system has 1g of P. See the issue?

 

I didn't make myself clear, my bad. By "net" export, I really mean relative net export, as in %; not absolute, as in mass. If I am adding x amount of Po via food, I would want my export to equal that obviously, otherwise it builds up fast somewhere else.

 

 

When dealing with Liebig's law of the minimum, if you are removing the part of the excess, you really are not doing anything because it is not limited.

 

Re: algae biomass, If the excess is removed quickly enough then P can become limiting, and then the biomass shrinks. There is an equilibrium point somewhere which as aquarists, you would have to determine what that is, and what the benefits might be.

 

In my tank, I am making an attempt to feed often and regularly, and relying on an ATS to export some (how much..?) of the runoff, of which there is plenty. It is not a nutrient limiting system. It never will be. I do water changes. I siphon occasionally. I might add some GFO. I will be adding periodic replacement of sections of substrate to my husbandry. If algae wasn't helping me, then it would fail to grow.

 

 

 

The substrate reaching a saturation point is my biggest concern, to be honest. At that point, stasis flies out the window.

[penfold2]

One thing that keeps being brought up is the total amount of P in the system, as opposed to just the Pi dissolved in the water column. Are these other sources of P directly problematic, or is it just the fact that they can break down into free Pi? If they are not directly problematic, then isn't the issue just a matter of how efficient algae is at absorbing Pi? It wouldn't matter how much Po is in the system if algae is taking up Pi just as quickly as it is being produced.

 

I'm still working to keep up with all this, so tell me if I've got something wrong.