Zero Coraline algae growth - solved

[blasterman]

Awhile back I started a thread trying to figure out why my favorite tank has virtually no coraline algae growth. I recently solved the problem, and the results are pretty facinating. My entire scenario might have broader implications for LPS and especially SPS growers in general, but I'm still trying to wrap my brain around what I fixed.

 

Basically this tank is about two years old now, was moved from a 10 to a 15gal, is bare bottom, and is stocked with a good structure of rather old but stable LR. From the start coraline algae growth was sluggish and didn't last very long on seeder plugs or frags. However, some while back I started to have trouble with SPS, and given I wanted to spend more time with softies and zoas anyways I gave away my SPS. I know some of you guys have good luck with SPS in small tanks, but I've never liked the combination, wanted to focus on other things and high nutrient levels don't work well with SPS.

 

Anyways, further on down the road I started to notice my LPS; Acans, candy canes, etc., started slowing down. I actually lost a colony of Acans and a couple of candy canes for no known reason, and the only symptom was good polyp growth with almost no skeleton growth. At this point I decided to focus some effort of solving the problem.

 

I tried every possible water param and tweak I could think of. Changed salt mixes, altered water change frequency and source water, changed alk and calc levels and every permutation, raised/lowered mag levels, yadda, yadda, yadda. I triple checked my alk/calc levels with various reef stores to confirm, and stumped them as well. Nothing worked. What I *did* learn is lots of things like high mag levels. Even zoas and palys like sky high mag levels, and GSP grows like a horror movie. I've since removed most of the GSP from the specific tank thinking it was doing something negative, which is likely not the case.

 

After all this screwing around and increasingly trying random and illogical things I stumbled across only one thing that caused coraline to perk up just a tiny degree. By itself Purple-Up is just calcium carbonate powder with a bit of iodine and ionic calcium, but when combined with my own calk mix caused coraline to perk up for a day, lead me in the right direction. Maybe the fact I had a bare bottom tank was causing buffering problems which in turn kept calcium from being available.

 

So, I added 5 cups of generic crushed coral to the bottom of that tank, waited a day for the haze to clear, and like magic coraline algae patches that had turned white over a year ago came back to life. Within two days my Acan and Candy Cane colonies showed obvious improved health and branch growth, and a couple digipora frags are starting to show improved tip growth. All this....from adding a bit of stupid crushed coral to my tank and nothing else.

 

Ok, so what was wrong and what was fixed, and why? Obviously LR by itself has little buffering ability, and that's lesson one. It's surface likely gets bound up with carbon over time and becomes inert. Next, water params might not tell us the whole story regarding the actual buffering capability of the tank. Alk and calk params had no affect on anything in the tank - but adding calcium carbonate gravel (crushed coral) did. Given that substrate is a huge variable in various tank set-ups *maybe* it's a bigger player in terms of tank chemistry than we think.

 

At this point I'm likely going to invest in a digital pH meter because I really need to track it with precision to see what's going on and why, but at least I fixed the problem. Might be worth a shot if others are having the same problem to change out some of their substrate with fresh and see if it fixes things.

[Bishop]

My Coralline seems ok as far as I know. The tank is about 6 months old now and has had spots of coralline popping up for a while now. The growth is slow but it is there. Calcium is always at a low 380. I use Tahitian moon sand so this does nothing for buffer. I do try to maintain my water changes and have plenty of live rock though.

[blasterman]

After what I experienced I'd be very leary of using anything other than a calcium-carbonate based substrate, at least for optimum SPS growth. Maybe a reactor would negate the problem....I dunno.

 

The picture below shows some coraline on the bottom right of the Acan plug. It was 'snow white' a few days before adding the CC, and was so for over 6months. The Acan is happier as well.

[Zoafreak]

wow very impressive work you did. I'm glad i read this because i wasthinking of setting up my frag tank as a BB

[Bishop]

ok, Let's say you are right and the addition of calcium based sand really makes a difference. It's most likely just that, "the addition of" I imagine that if you went months without live rock and all the sudden added some clean rock to your tank you would get the performance buffering.

 

What ever had caused your Live rock to stop buffering the calcium level is surely to effect your sand once it gets established within the tank. Adding the new sand to your established tank may have had the dame effect ad putting the whole bottle of purple-up in your tank. Naturally in a time-release fashion.

[blasterman]

Good points I agree with, and I want to emphasize we're talking about time variances as well.

 

Crushed coral or calc-carb based sand is going to have a far greater buffering capacity than LR simply by virtue of it's much larger surface area. I mean, they put crushed coral in calcium reactors and not chunks of LR. Plus, as I recall the carbonate structure of LR can be quite different than CC or sand and certainly denser.

 

Given that purple-up is just calc-carb powder the chemistry is going to be similiar if not identical to having calc-carb based substrate in the first place. This is why Purple-Up generates so much laughter because you are just adding ground up sand. In theory, the powdered aragonite should bind up free C02 and let any remaining ionic calcium be available. I don't entirely buy it because the effect would be very short, but I just showed than an influx of crushed coral had a very positive effect on calcium utilization.

 

My obvious concern is how long this will last, which is why perhaps monitoring pH digitally might be the only way to track it. This is also why I was careful to measure how much was put in the tank. A *lot* of reefers are struggling with coral growth in small tanks, and scratching our heads at adequate calcium levels. If adding a few pounds of fresh CC in a sump or back filter 're-charges' the chemical buffer for a long term, then I say go for it.

[jpfishfan09]

Blasterman, just curious as to what kind of lighting do you use?

[HecticDialectics]

IRC, crushed coral/argonite sand work as "buffers" by dissolving in low pH. To dissolve in any appreciable quantity pH normally has to dip below 6.7. In a normal reef tank with a pH of 7.7-8.2, the amount of dissolution is near negligible. The way it buffers is by dissolving into calcium and alk... so if your calcium and alk levels were fine, it wasn't that. Did you never check your pH before?

 

Also what do you mean the surface of live rock gets "bound" up with calcium? I'm unfamiliar with how carbon makes calcium carbonate insoluble in low pH levels...

 

Finally, I think it may be a lot less related to chemistry and much more related to biology. Bare-bottom tanks tend to be super-low nutrient... trace nitrates, etc. Low nutrient tanks tend to have crappy coral color without the addition of ridiculous supplements.

[Reef Miser]

I always thought that alkalinity was a measure of buffering capacity. If your alk checked out to be ok, how is the addition of substrate increasing your buffering but not impacting your dKH #s? I'm not knocking your experience/observations, just trying to get a handle on what is going on here.

[Weetabix7]

Curious.....

I'd be interested in hearing more discussion on this.

[acropora1981]

I'd be willing to bet you'd get the same results dripping kalkwasser. Try the digital pH meter - I had some issues like you desribed last year, and when I got a digital meter, I realized that the tank was dipping down into 7.5-7.6 at night. Kalkwasser completely re-invigorated the tank, and has brought many corals back from the brink. I know with quite a bit of certainty that low pH was the problem. Before I went to kalkwasser, I tried using NaOH (pharmaceutical grade) to bump up the pH only. On day 1 of that test my corals started to open back up for the first time in months. By day 3, corals were magically coming back to life all over my tank.

 

Lack of skeletal growth and poor coralline growth would be a good indicator of chronic and excessive low ph, because corals have an increasingly difficult time building skeleton as the pH decreses; once you hit about 7.6-7.7 it becomes quite difficult to form calcium carbonate. I read a lot of posts saying 'don't worry about pH, just stability'. I also thought this to be true for about 12 years. I think actually that it is true within a certain range; go outside that range though, and things will start going wrong.

[blasterman]

Blasterman, just curious as to what kind of lighting do you use?

 

LED

 

To dissolve in any appreciable quantity pH normally has to dip below 6.7.

 

Molecular dissolution of calcium carbonate occurs at a much much higher pH than that. Nobody is manually dosing calcium in our oceans, and yet the pH of the Atlantic shorline is far above 6.7 and there's plenty of calcium.

 

Did you never check your pH before?

 

Read my post. I track my pH very close - and the more I think about this the more I'm skeptical if our test kits are reading truly available calcium. Or, different kits are reading different types of calcium. I cranked my calk and alk level off the chart, and yet couldn't grow any coraline and had to give away my SPS because they stopped growing. A few cups of crushed coral and now things are taking off with no other parameter change. My pH has gone up just a nudge.

 

I'm unfamiliar with how carbon makes calcium carbonate insoluble in low pH levels...

 

Once calcium starts getting bound up in long carbonate molecules it requires lower and lower pH levels to free it up and it becomes less and less available for corals. The stuff that forms in the corners of your tank or in rock crevices that precipitates out of your water is nearly inert and I would suspect has a different molecular structure than crushed coral or typical aragonite. Also, the amount of organics and free carbon in your living room tank would likely require several hundred if not thousand cubic meters of seawater to reach the same concentrations. That crap all binds with calcium and rock surfaces in your tank, and a skimmer can only grap so much of it.

 

I've noticed that my over-all zoanthid growth has slowed down after the addition of crushed coral. Some colonies are still recessed, but starting to open. Palys and large zoas like gobstoppers don't care. Acans and some additional SPS frags are clrealy showing improvement.

 

Finally, I think it may be a lot less related to chemistry and much more related to biology.

 

No. It's chemistry.

 

If your alk checked out to be ok, how is the addition of substrate increasing your buffering but not impacting your dKH #s?

 

Not entirely sure, but I wouldn't think that's what's going on. With a bare tank with no CC or aragonite sand any calcium added to the tank in any form likley get's bound up in CO2 / carbon as soon as it hits the tank. Yet test kits now and then aren't showing any difference in alk or calcium. Like I said....maybe test kits are reading unavailable calcium and obviously dKH won't care either because the calcium is there, but just in molecular form.

 

I'd be willing to bet you'd get the same results dripping kalkwasser

 

It's *possible*, and I appreciate the input because that's a track I was on. I didn't try a drip, but I did try splitting up my calcium dosing to several times a day to try an emulate what a drip would accomplish. However, all this did was produce more precipitate in my tank and start burning the tips of the few SPS I had left. Again, my theory is that any available calcium I added just got bound up in carbon / CO2 because there was nothing else locking it up (crushed coral). This also explains why really big tanks tend to grow SPS so well with all that crushed coral on the bottom.

 

Until I talk to a chemist I'm not going to trust test kits, and certainly no claims of actual calcium levels. I've also seen too many small tanks in my lifetime having the same problems to know it's just not my set-up.

[sean151]

It's not like hydrothermal vents, water entering the ocean, organisms breaking up the CaCO3 or temporary acidification in certain spots of the ocean adding free Ca and alkalinity. Also, the fact scientists use tests similar to the Salifert ones kind of add legitimacy to the numbers.

[acropora1981]

It's *possible*, and I appreciate the input because that's a track I was on. I didn't try a drip, but I did try splitting up my calcium dosing to several times a day to try an emulate what a drip would accomplish. However, all this did was produce more precipitate in my tank and start burning the tips of the few SPS I had left. Again, my theory is that any available calcium I added just got bound up in carbon / CO2 because there was nothing else locking it up (crushed coral). This also explains why really big tanks tend to grow SPS so well with all that crushed coral on the bottom.

 

Until I talk to a chemist I'm not going to trust test kits, and certainly no claims of actual calcium levels. I've also seen too many small tanks in my lifetime having the same problems to know it's just not my set-up.

 

Burning the tips! I don't see how that would happen with properly applied kalkwasse. How would properly dripped kalk burn the tips? You can't just add a bunch at a time; its MUST be dripped. Any other application of kalk will spike the pH, cause a large amount of precipitation (calcium will precipitate out quite nicely at pH>8.5). Adding a tablespoon or even just a few millilitres will cause a localized pH spike, precipitation, and likely stress to corals and fish. Especially in a smaller tank.

 

Also, have you never seen the amazing results many reefers get using bare bottom tanks? For reference, see the current TOTM @ reefcentral.com My own small SPS tank has never looked better now that it is barebottom.

 

Certainly tanks with crushed coral or calcium based substrates have better buffering capacity than bare bottom tanks. Thats not news.

[Weetabix7]

Some good discussion here, lets keep it going.

If I recall correctly, we got away from using Crushed Coral as substrate in Reef Tanks because it was seen as a detritus trap, right?

Were there other reasons?

Why would Crushed Coral buffer better than Aragonite based sand?

[acropora1981]

Some good discussion here, lets keep it going.

If I recall correctly, we got away from using Crushed Coral as substrate in Reef Tanks because it was seen as a detritus trap, right?

Were there other reasons?

Why would Crushed Coral buffer better than Aragonite based sand?

 

Sorry what I mean is that tanks with calcium based substrates tend to have a higher buffering capacity than bare bottom tanks Which is why many bare bottom users, especially those who use calcium reactors, use kalkwasser.

[blasterman]

I tried dosing a less than 1 ML increments starting from a large water change. Not exactly dumping it in.

 

I held calcium at varius levels and soon tracked it off the scale. Obviously alk held steady because nothing was using the calcium - other than C02 to hump it and precipitate out. I repeat, I tried calcium levels all over the place from well over 600 to sticking with normal salt concentrate levels. No matter what I tried with calcium nothing worked. No combination of magnesium or alk helped either although mag seems to be being used up faster now.

 

Also, I'm a firm believer that while salt mixes can vary in terms of exact chemical composition, 20% weekly water changes in a tank with a medium to light coral load should promote growth. Not nearly as vigorous as adding calcium of course, but growth should still be decent. I tried three different salt brands and tested several different RO sources and no effect. If aggressive water changes can't get coraline to take off and doesn't impress LPS, something else is wrong.

 

I also tried mixing my calc using different concentrations and different amounts of vinegar to hyper saturate the calcium. No effect, although it's working pretty good now.

 

Also, have you never seen the amazing results many reefers get using bare bottom tanks?

 

I've been reefing for over 20 years and have seen pretty everything, and back in the early 90's had a thriving BB tank in a 55. However, I've seen 100x the number of smaller tanks where water params are testing ideal and SPS growth is sluggish and the owner starts blaming LEDs or some stupid sh_t like that. Also, I like to use coraline as a 'test pigeon' because one thing I've never seen is a thriving SPS tank without obnoxious coraline growth. So, while coraline is a nuisance to many of us, lack of it's growth was just a symptom and not the goal.

 

While TOTMs look cool, they are often the exception and not the rule. 50 people could likely try the exact same combination and not get the same results. I look for things that various reef tanks with distgusting amounts of SPS growth have in common and they all are; large, and are using a reactor or drip.

 

Since I don't want a big substrate in my tank I'm going to try circulating tank water through an external bucket full of CC at a slow rate and see what happens. I should also bring up the number of tank owners that swap out their substrate every once in awhile and report improved health.

[acropora1981]

I should also bring up the number of tank owners that swap out their substrate every once in awhile and report improved health.

 

That I can agree with, and have seen first hand. Though I think the same result should be attainable by simply rinsing the substrate in a mild acid solution. I also beleive that if the tank has sufficient sand stirrers, that the outer coating of the sand should be continually removed by acidic reactions in the gut of various worms and saft sifting creatures, allowing for contiued buffering capacity.

 

I also agree with you that coraline growth is a great indicator of tank health, overall. Though I see many SPS tanks where the main display is much too bright for it to thrive, but it thrives in the sump or less lit areas like skimmer or elsewhere.

 

I would like you to do this:

 

1. Get a digital pH meter. I was in the hobby 15 years before I bought one, and I now beleive them to be a highly useful diagnostic tool. You may find they your night time/morning pH is lower than you think on a regular basis.

 

PS, I think your ideas are interesting, which is why I am posting here So I hope I do not offend you by challenging you a bit.

[rO.oster]

great discussion

[HecticDialectics]

No. It's chemistry.

 

 

 

Not entirely sure, but I wouldn't think that's what's going on. With a bare tank with no CC or aragonite sand any calcium added to the tank in any form likley get's bound up in CO2 / carbon as soon as it hits the tank. Yet test kits now and then aren't showing any difference in alk or calcium. Like I said....maybe test kits are reading unavailable calcium and obviously dKH won't care either because the calcium is there, but just in molecular form.

 

No you seem to have completely misunderstood what I was talking about with it being biology, not chemistry. Adding crushed coral probably increased levels of bacteria and nutrients that you didn't have running bare-bottom that helped color up the coralline. The biology hypothesis has absolutely nothing to do with calcium levels, which your test kit suggests was just fine. There are people who are able to keep colorful coral and coralline running bare-bottom, but as I said, they normally run zeovit systems adding a bunch of extra nutrients (bacteria, aminos, etc.) themselves.

[HecticDialectics]

Again, my theory is that any available calcium I added just got bound up in carbon / CO2 because there was nothing else locking it up (crushed coral). This also explains why really big tanks tend to grow SPS so well with all that crushed coral on the bottom.

 

Effect of Organics

 

Organic materials have the potential to impact calcium sensing in two main ways. The first is by binding directly to the membrane, altering its potential, or fouling it so that calcium cannot enter. The second is by binding calcium in solution, making it less likely to enter the membrane. Strong binding of calcium by the chelator EDTA, for example, can make it completely unavailable for sensing by the membrane.

 

In order to test how likely these issues are to matter to reef aquarists, I started with the sample of artificial seawater made using Instant Ocean that resulted from the pH studies above, and added calcium chloride (part of another study). I then added skimmate from my aquarium's skimmer equaling about 2% of the liquid's volume, in order to simulate the possible effect on calcium sensing of a significantly higher level of organic materials. Two percent was chosen fairly randomly to simulate a high organic level without altering the water so much that it wasn't likely to be encountered by aquarists.

 

Over the course of 30 minutes, I noted no change in the calcium reading, indicating that any effects due to organics are likely to be unimportant for most reef applications.

 

http://www.reefkeeping.com/issues/2005-04/rhf/index.php#11

 

There ya go.

[skimmerdude]

This is a pH effect until proven otherwise.

[HecticDialectics]

This is a pH effect until proven otherwise.

 

 

He said he monitors pH and that it was fine, lol.

[lakshwadeep]

It's best to stick with the water chemistry of reef tanks. pH in the oceans is an extremely complicated parameter that is going to have greatly different influences (the sun, water currents and tides, precipitation, geochemical reactions, etc.) than what is found in closed systems.

 

Calcium carbonate is unlikely to dissolve much in higher pH values than listed by hectic; otherwise livestock with calcified skeletons would have problems at "normal" pH numbers due to instability of the calcium carbonate. The only way it would dissolve is if there is localized (sometimes biologically induced) decreased pH, which then raises the question of how you would test those localized pH values.

 

Like others have said, it's misleading to say a hobbyist calcium test kit is inaccurate based on what a hobbyist pH test kit says. Calcium is not completely "bound up" when dissolved.

 

It's confusing what is meant by calcium "getting bound in long carbonate molecules".

 

This is a good article on the subject of common yet misleading methods used to influence carbonate chemistry (i.e. buffering), and sand buffering is #3.

Aragonite sand and live rock can and do dissolve very slowly in our aquaria, and in so doing provide a tiny buffer against calcification. This buffer effect, however, is so small as to be essentially inconsequential and is sufficient to offset only an extremely low rate of calcification. The amount of calcification we could obtain after a year with supplementation would take perhaps 25 yrs to achieve by relying on the dissolution of our sand bed and live rock. Clearly this method is a poor choice.

http://www.advancedaquarist.com/2009/7/che...y/document_view

[brandon429]

Blaster what about the bare bottom tanks we have here that have coralline painted as the carpet and paneling...every once in a while on the top page I'll see one rolling through the pictures and it will be a point to stop by and complement them.

 

it never fails each and every time they are doing only water changes, right when Id be sure it was a dosing of some kind. the number of people getting coralline on just water changes really kind of shocks me.

 

its so common now I have trouble pinpointing it to anything. although I don't doubt the substrate swap affected your tank it makes it hard to draw inference when these guys and gals have coralline plated in whorls and all they did was use tropicmarin salt...frustration...water changes alone didn't work for me, I had to dose C balance to get the plague.