Low alkalinity and other questions ☺️

[D.J.]

Hi Everyone,

I feel like this might be a beginner question, but I’ve been in the hobby for a while with mild success...so, posting in general 😂. I’ve been in the hobby for years but had to take a break and have had this tank for nearly a year. 

 

Issue: alkalinity on my tank has been low for a while and has dropped pretty quickly over the past few weeks, but calcium is high. I have recently changed from using Tropic Marin Pro Reef to their Syn-Biotic because I realized the pro reef is designed to pair with dosing of alk/calcium and syn-biotic has closer to the parameters I want without dosing. I plan to use two part eventually. 
 

Other issue is that I have an algae out break that I’ve been fighting for several months but think I’m making progress on. I know the primary cause was due to a multi-week emergency that required a friend to take care of the tank and I had to quickly buy a bunch of filtered water from the store which likely leached phosphates into the tank and clogged the filtration, compounding the problem. I’m back in control of the tank, filtering my own ro/di to zero tds. I also did several rounds of the Dr Tim’s algae removal process on BRS, using refresh and waste away to reduce phosphates and eat the algae with bacteria. 
 

Setup:  about one year old tank, slowly added stock over the first 9 months or so, nothing added since. 

- 14 gallon innovative marine peninsula all in one

- AI hydra 32 (turned down pretty far with par between 150-270 throughout the tank at rock level)

- tunze 6050 controlled by apex with ramp up/down steadily throughout the day

- refugium with chaeto and IM chaetomax light running for 12 hours per day (opposite display light). Emptying chaeto once per month, growth has slowed over the past few months and I’ve corrected algae issues

- filter pad changed every 1-3 days

- extra biological filtration of four bio blocks in the filtration chambers

Feeding

- automatic feeder once per day giving mixture of dry PE Mysis pellets, Saki-Hikari herbivore pellets, and reef chili

- frozen PE mysis once per day with a few drops of coral amino

- one per day 0.5 ml of coral snow

Stock

- 2 captive bred “designer” clown fish

- 1 captive bred mandarin

- 1 captive bred court jester goby 

- 1 pink streaked wrasse

- mixture of zoas that have grown from 8-10 polyps to 50+
- blasto that started as one polyp and has recently sprouted about 7 more polyps

- favia that started as two polyps and is still two but slowly starting to split to a third

- acropora frag that has slowly and steadily grown I’ve the past 6 months

- anacropora frag that’s grown a bunch recently!

 

Parameters

- temp 78-79

- phostphate 0.03

- alk was 8.12 in October and has steadily dropped to 6.38 dkh today 😖😖

- calcium fluctuates a bit but hovers around 500 🙄

- pH fluctuates from 7.83-8.02 between day/night

 

sooo, if you made it this far, thanks for reading it all 😬. My question is, does anything look really off here?  I’ve never been successful enough in reef keeping to need to use two part to make up for coral consumption. Is it realistic to need to dose for alk but not calcium yet?  Is something else going on?  Should I wait until the algae clears up completely before I do anything else?  I’ll post some pics below. Thanks everyone for help, in advance. 

 

 

[D.J.]

July 2020 pictures

[D.J.]

Pictures from this week

[D.J.]

One more from today after I cleaned the algae a bit 😅

[D.J.]

Oh, forgot. Maintenance schedule is 2 gallon water change per week. 3 weeks per month I vacuum the sand and the 4th week I clean out back of the tank and soak the pumps in citric acid 

[I'm Batman]

I didn’t see what your nitrates were measured at, and relative to alk I included a recent post below. 
https://www.reef2reef.com/threads/what-caused-my-alk-spike.784448/

Also according to BRS, Alk and Calcium are on a teeter- totter over Magnesium. According to their graph, your calc at 500 would put your alk around 6dKH which is about in line with your measurement. 
 

 

[Tamberav]

I would just do a large water change to get alk in line and then test for consumption and dose 2 part. Yes, you dose both components based off alk consumption. You also need to test magnesium too so you know that is in line first.

 

That is a very large bioload for your size tank and likely contributing to the algae issue. It makes for a uphill battle. 

[D.J.]

Thanks for the responses. So...since calcium and alk teeter totter, the calcium is high because alk is low. That means I probably do need to start dosing alk, which will fix the calcium and then I’ll need to dose calcium to keep it there?

 

regarding the recommendation to do a large water change, just tried that. I did a 5 gallon change each of the past two weeks, after I switched salts. 
 

I feel like the bio load is a little high, but I also have a large natural filtration with the large surface area (decent amount of rock, sand, and bio blocks), and heavy output through regularly changed filter pad and chaeto with long photo period. All the fish are pretty small except the clowns. 

[I'm Batman]

By the way, where is that refugium at? Is it in the back chamber? 
 

I have so many questions you were pretty detailed. I was looking at your bioload. How do you keep the mandarin fed, it just eats frozen and is cool with the clowns? 

5 hours ago, D.J. said:

does anything look really off here?

What are your nitrates at?

 

3 hours ago, D.J. said:

after I switched salts.

Also salt switching that’s another one to point to - now your Params have to balance out. Reefers

 on occasion end up switching back to their old salts to get on track. 
 

How long are you mixing your salt? Apparently that makes a difference. BRS did great work for us in 6 minutes with this relevant to your salt mix. 
 

[I'm Batman]

5 hours ago, D.J. said:

I’ve never been successful enough in reef keeping to need to use two part to make up for coral consumption. Is it realistic to need to dose for alk but not calcium yet?

The only way to tell is to have a testing and dosing regiment. I’m leaning toward spending the $1,500 on a Neptune with trident just because unless it’s convenient, it gets tiring testing.

 

I test on Sunday before a water change two 20 gallon AIO tanks and dKH + PO4 on Wednesday.

- Red Sea Pro Calcium

- Red Sea Nitrate

- Red Sea PH
- Hanna Salinity

- Hanna PH

- Hanna dKH (Sun & Wed)

- Hanna Phosphorus PPB (Sun & Wed)

- Salifert Calcium

- Salifert Magnesium

In my 20g Peninsula I’m dropping 6 drops each of B-Ionic Part 1 & 2 . Not doing water changes because of Dino. Was adding prime & Amquel to top off water - bottomed our nutrients - not enough feeding - bam - red tide. 

 

In my 20g IM Nuvo, water changes takes of care elements. 
 

Ultimately if you feel like you need to dose something, test, if you are chasing a number, dose, then test the next day. I was testing twice a day PO4 for and dosing found the right balance for dosing NeoPhos. Also for B-Ionic... “everybody’s using it!” Tested and found I can benefit. Kalkwasser is another element I’ve been tinkering with.

 

Test and adjust - test again! Make sure you have enough reagents!

[mcarroll]

9 hours ago, D.J. said:

I know the primary cause was due to a multi-week emergency that required a friend to take care of the tank and I had to quickly buy a bunch of filtered water from the store which likely leached phosphates into the tank and clogged the filtration, compounding the problem.

That is extremely unlikely.  That's not how phosphates get into your system, and that's not what causes algae to bloom out of control.  👍

 

9 hours ago, D.J. said:

I also did several rounds of the Dr Tim’s algae removal process on BRS, using refresh and waste away to reduce phosphates and eat the algae with bacteria.

🤦‍♂️ (Not your fault....they market themselves very well.)

 

This is not how you handle an algae outbreak.

 

10 hours ago, D.J. said:

refugium with chaeto and IM chaetomax light running for 12 hours per day (opposite display light). Emptying chaeto once per month, growth has slowed over the past few months and I’ve corrected algae issues

- filter pad changed every 1-3 days

- extra biological filtration of four bio blocks in the filtration chambers

This is a dangerous set of routines that has derailed many a tank...I would go easy on all three of these and even consider removing the extra filter media.

 

10 hours ago, D.J. said:

Feeding

- automatic feeder once per day giving mixture of dry PE Mysis pellets, Saki-Hikari herbivore pellets, and reef chili

- frozen PE mysis once per day with a few drops of coral amino

- one per day 0.5 ml of coral snow

I would consider dropping the coral food, drops of coral additive as well as the "snow".  Your fish produce all of that every time you feed them.  👍

 

I would also generally be conservative with the dry foods and generous with the frozen.

 

10 hours ago, D.J. said:

phostphate 0.03

This is as low as you'd want to go with phosphates.  Higher would be better, generally speaking, in terms of margin of safety and also in terms of coral health IMO.

 

10 hours ago, D.J. said:

alk was 8.12 in October and has steadily dropped to 6.38 dkh today 😖😖

Hopefully you're testing alk more than once every three months?  😉

 

But seriously, most of the stony corals you listed won't remain happy with alk swinging or with it that low.  If you aren't already, consider testing daily to see if you can detect the usage rate of your alkalinity yet.  Calcium moves a lot more slowly (magnesium even slower), so that might not show up on a test yet.

 

10 hours ago, D.J. said:

Should I wait until the algae clears up completely before I do anything else?

FYI algae likes the same conditions that your corals like....so you can let go of ideas like "starving the algae".  If you were successful, you'd also starve your corals.

 

The reason that algae doesn't take over healthy reefs is mainly one thing:  herbivory

 

You haven't mentioned your cleanup crew...

 

So I'm guessing that's your problem – lack of cleanup crew.  

 

Another problem could actually be your starvation approach....this actually has the tendency to cause algae since algae deals with it just fine (starvation is periodic for algae in the wild), but competing organisms DO NOT deal with it well at all.

 

I would also consider shutting down the refugium until your algae issue is resolved.  Then decide if you want to redeploy it later on.  You do not want more algae growing in the system.  If there are excess nutrients, you want OTHER THINGS to use them so that your live rock matures and grows all the things that can help prevent hair algae from getting a foothold in the first place.  (Like coralline algae, for example.)

 

Here's how to pull algae – use this technique.  Also use his guidance for stocking snails.  (The other guidance he gives does not apply to your tank.  E.g phosphate removers)

 

[D.J.]

10 hours ago, I'm Batman said:

By the way, where is that refugium at? Is it in the back chamber? 
 

I have so many questions you were pretty detailed. I was looking at your bioload. How do you keep the mandarin fed, it just eats frozen and is cool with the clowns? 

What are your nitrates at?

 

Also salt switching that’s another one to point to - now your Params have to balance out. Reefers

 on occasion end up switching back to their old salts to get on track. 
 

How long are you mixing your salt? Apparently that makes a difference. BRS did great work for us in 6 minutes with this relevant to your salt mix. 
 

Yep, refugium is in the back center compartment, I use the inTank fuge compartment for it. I actually have room for a couple of bio blocks and the chaeto in it. 
 

i haven’t been checking nitrates regularly since the cycle finished but will see if I have a test kit that isn’t expired. If not, I’ll order one and check it out. 
 

the mandarin is getting chubby!  He does eat frozen/dry foods readily. He seems to like the reef chili, which I’ve read is pretty normal for the captive bred mandarins. Everyone in the tank is completely peaceful with the exception of minor chasing during feeding time, which I think is pretty normal. Honestly, if I did it again, I would probably just not get the clowns to reduce bio load. But, I hope to have a full reef soon to suck up the nutrients anyway!

 

I was mixing salt for several hours and letting it sit for a while (which I learned from the BRS investigates!) but the synbiotic suggests to use it as soon as the salt fully dissolves because of the bacteria that’s in it. I actually learned the hard way that letting it sit too long will have a negative impact on alkalinity (also in a BRS video). 

[D.J.]

6 hours ago, mcarroll said:

That is extremely unlikely.  That's not how phosphates get into your system, and that's not what causes algae to bloom out of control.  👍

 

🤦‍♂️ (Not your fault....they market themselves very well.)

 

This is not how you handle an algae outbreak.

 

This is a dangerous set of routines that has derailed many a tank...I would go easy on all three of these and even consider removing the extra filter media.

 

I would consider dropping the coral food, drops of coral additive as well as the "snow".  Your fish produce all of that every time you feed them.  👍

 

I would also generally be conservative with the dry foods and generous with the frozen.

 

This is as low as you'd want to go with phosphates.  Higher would be better, generally speaking, in terms of margin of safety and also in terms of coral health IMO.

 

Hopefully you're testing alk more than once every three months?  😉

 

But seriously, most of the stony corals you listed won't remain happy with alk swinging or with it that low.  If you aren't already, consider testing daily to see if you can detect the usage rate of your alkalinity yet.  Calcium moves a lot more slowly (magnesium even slower), so that might not show up on a test yet.

 

FYI algae likes the same conditions that your corals like....so you can let go of ideas like "starving the algae".  If you were successful, you'd also starve your corals.

 

The reason that algae doesn't take over healthy reefs is mainly one thing:  herbivory

 

You haven't mentioned your cleanup crew...

 

So I'm guessing that's your problem – lack of cleanup crew.  

 

Another problem could actually be your starvation approach....this actually has the tendency to cause algae since algae deals with it just fine (starvation is periodic for algae in the wild), but competing organisms DO NOT deal with it well at all.

 

I would also consider shutting down the refugium until your algae issue is resolved.  Then decide if you want to redeploy it later on.  You do not want more algae growing in the system.  If there are excess nutrients, you want OTHER THINGS to use them so that your live rock matures and grows all the things that can help prevent hair algae from getting a foothold in the first place.  (Like coralline algae, for example.)

 

Here's how to pull algae – use this technique.  Also use his guidance for stocking snails.  (The other guidance he gives does not apply to your tank.  E.g phosphate removers)

 

Hmmm, thanks. Lots to think about and I’ll get on watching the video. 
 

you’re right, I’m not testing alk every three months. I test it weekly and periodically throughout the week. The range I gave was to show the drop over time. I’ll start testing daily to see if it’s appropriate to start dosing alk. 
 

for cleanup crew, I do have a mixture of snails and blue leg hermits. I also added the court jester for his algae eating tendencies, and he does nip at it. Not many small herbivore fish for a nano, unfortunately. 
 

My goal is definitely not to have a low nutrient system. The goal is heavy in/heavy out - feed plenty to get everyone what they want and then suck out the extra/waste through the filter pads and fuge.  The bio blocks are mostly to support the fairly large bio load in the tank. 0.03 phosphate was my most recent reading and it’s fairly consistent at that point, the average over the past 6 months is 0.034 going up to 0.06 (though I didn’t test while my friend was taking care of the tank and did a pretty sizable water change before I tested once I was able to maintain it again). Besides those few weeks, I’ve never been overly concerned about phosphate levels and haven’t been actively trying to lower them from the levels they are at

[mcarroll]

On 12/21/2020 at 10:45 AM, D.J. said:

for cleanup crew, I do have a mixture of snails and blue leg hermits.

Hermits I consider more as scavengers...even the little blue legged ones.  Which kind(s) of snails do you have and how many?

 

On 12/21/2020 at 10:45 AM, D.J. said:

The goal is heavy in/heavy out - feed plenty to get everyone what they want and then suck out the extra/waste through the filter pads and fuge.

On 12/21/2020 at 10:45 AM, D.J. said:

The bio blocks are mostly to support the fairly large bio load in the tank.

That would hypothetically be a good plan for a fish tank, but (thankfully, it's the whole object for us) reefs aren't nearly that straightforward.  Quite the opposite in some major ways.  

 

In a nutshell, reefs intensively conserve, generate and recycle nutrients, so it's more of a cycle than the in-out pattern you have described.  That cycle actually makes the "heavy out" part of your plan a fundamental mismatch for your reef.  (Lots of new reefs go through this phase where they are over-filtered at the beginning.)

 

Check out the articles I've saved in the coral section on my blog...many relate to nutrients and nutrient issues:  https://reefsuccess.com/tag/coral/

 

Personally, I wouldn't employ any of those "extras" (eg refugiums, bio bricks, et al) on a proactive basis....only as-needed.  (If a refugium is a primary part of your display, then it's a different story....you'll have a care regiment just for it in that case.  It wouldn't be regarded simply as a part of the filter system.)

 

Live rock and its biology are supposed to be doing all of that stuff.  Water changes (which natural reefs also experience) and dosing (for stony corals) do most of the rest, more or less, depending on your design.

On 12/21/2020 at 10:45 AM, D.J. said:

0.03 phosphate was my most recent reading and it’s fairly consistent at that point, the average over the past 6 months is 0.034 going up to 0.06 (though I didn’t test while my friend was taking care of the tank and did a pretty sizable water change before I tested once I was able to maintain it again). Besides those few weeks, I’ve never been overly concerned about phosphate levels and haven’t been actively trying to lower them from the levels they are at

0.03-0.06 isn't a meaningful swing. 👍 Both numbers are actually very low in the overall scheme of things.  I like 0.10 ppm as a number that's still "low" but with a nice margin of safety from zero.  

 

Higher numbers really are fine too though.  My system is old, but seems to run at 1.0+ ppm (nitrates "high" as well) and not have any problems. Corals grow pretty fast and look great.  👍

 

I'd say try to let the system do what it wants in terms of nutrient levels.  The only thing that should make you intervene is if nutrients start going toward zero.   (In the long run, as the system matures and its capacity to conserve and recycle nutrients increases, even that can be less of a concern.)

[D.J.]

Mixture of snails from reefcleaners.org. I think there are 7 nerites that appear to do most of the work, ceriths (dwarf and Florida, though the Florida didn’t do well and there’s only one or two left... the hermits seem to like them), and a bunch of nassarius. 
 

I watched the video you linked in your first post. I was already pulling out as much algae as I could, but the part about putting the snails where you want them was helpful. The nerites wanted to hang out on the glass all the time. I’ve been moving them to the rock work a couple of times a day and have noticed a pretty big impact 👍

[mcarroll]

17 hours ago, D.J. said:

a bunch of nassarius

Combined, you have a ton of scavengers.  Sounds like a thin crew of herbivores.  If there's any way for you to do it, consider swapping most or all of your scavengers (hermits and nassarius) for an equal number of herbivorous snails.  

[phinatic]

On 12/21/2020 at 12:31 AM, mcarroll said:

This is a dangerous set of routines that has derailed many a tank...I would go easy on all three of these and even consider removing the extra filter media

@mcarrollReading this old thread about dropping alkalinity, but ran across this comment. What do you see as bad about these things?

 

On 12/21/2020 at 12:31 AM, mcarroll said:

refugium with chaeto and IM chaetomax light running for 12 hours per day (opposite display light). Emptying chaeto once per month, growth has slowed over the past few months and I’ve corrected algae issues

- filter pad changed every 1-3 days

- extra biological filtration of four bio blocks in the filtration chambers

 

Changing the filter pad would just polish the water. The extra bio blocks shouldn't be an issue as long as you have strong flow through them. I keep a sponge in front of mine in the chamber to keep detritus out of the ceramic and just flush out the sponge on occasion. As for the refugium, it's pulling nutrient out of the water and competing with his pest algae. It's also hosting copepods that process the waste in the tank and feed his fish. The opposing light cycle is balancing the pH. I don't see anything wrong with these practices other than the monthly macro harvest. I would do it more frequently (and smaller) to avoid a swing in its nutrient uptake. What are you seeing as the issues?

[mcarroll]

🧟‍♂️

19 hours ago, phinatic said:

@mcarrollReading this old thread about dropping alkalinity, but ran across this comment. What do you see as bad about these things?

Well, first of all it's nothing personal.  It's biological – ecological! 😉

 

And it's a good question because this sorta flies in the face of convention in some ways.

 

In a nutshell, these things don't really mesh with a reef tank.

 

A reef tank is different from a fish tank, or even a planted fish tank.

 

19 hours ago, phinatic said:

Changing the filter pad would just polish the water.

Fish-only tanks need water polishing.  Not reef tanks.

 

Everything a filter pad would catch in a reef tank ought to be food for a fish, coral, another invert or microbe.  In some cases coral can be quite dependent on this food source.

 

19 hours ago, phinatic said:

The extra bio blocks shouldn't be an issue as long as you have strong flow through them. I keep a sponge in front of mine in the chamber to keep detritus out of the ceramic and just flush out the sponge on occasion.

Mainly, there's just no need.  Filtration is not a "more is better" situation.

 

With rare exceptions, we use a correct amount of live or dead rock, which provides surface area, denitrification, habitat, chemistry, et al.  It is superior in all aspects.  (Chemistry of aragonite is where it's at.)

 

Further, the bio-block media often tends to leach (eg aluminum).

 

Last, the extra surface area puts excessive pressure on NO3 removal, among other things.  

 

Arguably no tank needs excessive nitrate removal.  Kinda by definition, right?

 

But a tank that doesn't have excessive nitrates definitely doesn't need excessive removal.

 

Some folks treat nutrients like they are toxins....but what we are talking about are essential nutrients.  Nitrogen and Phosphorous.  Without them, new reef tanks don't grow.

 

 

19 hours ago, phinatic said:

As for the refugium, it's pulling nutrient out of the water and competing with his pest algae.

That's the conventional wisdom, and it's always considered a positive thing even out of context like on a new tank.

 

But without "extra" nutrients to pull out, what happens?  

 

And what nutrients are considered "extra" since these are essential nutrients for our corals?

 

It also doesn't really take into account how algae grows and how it gets access to essential nutrients like phosphorous.

 

A refugium is certainly going to compete with the display tank for N and P if it's lighted.  Even to some extent (primarily NO3) without lighting.

 

Unfortunately for the plan, corals are going to be the least-capable competitor in the display tank.  Not algae.  Algae have much more/better access to primary nutrients.  P in particular.

 

You fight algae blooms with herbivory not via nutrient levels.  

 

The only way to use nutrient levels to your advantage is *before* the algae blooms.  

 

Having a very small reservoir of dissolved nutrients (vs a large res.) will limit the size of the algae bloom when it happens.  Folks blow this opportunity when they load a new tank down too soon with too many fish all at once.  Ammonia levels shoot up, and that's a preferred food for algae.  It takes time for bacterial populations to adapt and grow to use up that ammonia.  Green algae are solar powered and *much* faster at spreading.  Once algae grows in, it is very adaptable to low- or high-nutrient conditions.

 

19 hours ago, phinatic said:

It's also hosting copepods that process the waste in the tank and feed his fish.

This much is fine.  But most folks don't leave it at pod farm/dark zone.

 

19 hours ago, phinatic said:

The opposing light cycle is balancing the pH.

That is actually a neat illustration of how CO2 levels interact with the water's pH level.

 

But I don't think it provides any benefit to the reef tank.  

 

Real reefs experience day/night pH changes.

 

BTW:  If anyone really has a CO2 buildup issue in their house, they need to get their house fixed ASAP.

 

(Almost nobody actual has a CO2 problem, but A FEW folks out there do.)

 

Those folks that actually have a CO2 problem (usually new ultra-well-sealed houses) should realize two things:

1. Extra CO2 in a healthy reef tank is just extra fertilizer that supports more photosynthesis.  It's beneficial.  
   But...  
2. Excessive CO2 is toxic to humans and will cause brain issues, mess with your sleep, etc.

The one person I've bumped into online that actually had a confirmed CO2 issue got his house fixed with an add-on to his HVAC that systematically lets more fresh air into the house.  No real difference to the tank, at least in the short term, but he and his family felt better immediately.

 

19 hours ago, phinatic said:

I don't see anything wrong with these practices other than the monthly macro harvest. I would do it more frequently (and smaller) to avoid a swing in its nutrient uptake. What are you seeing as the issues?

None of it is really called for in a standard reef tank.

 

And the core problem is that they all take nutrients (or food) that should go to the corals in the system.  An expert might be able to balance that out, but most folks don't.

 

BTW, most of the "extra" stuff was popularized back in the day with the goal of supporting silly-high fish loads...that would dictate ridiculous feeding rates...that inevitably resulted in NO3 and PO4 continuously building up.  (Scout out some threads from the 90's for the most fun.)

Whether stocking a tank super-dense like that has ever been a good idea could be discussed.  But going that route is definitely not recommended for a new tank or newb reefer.  So at least that subset of tanks really shouldn't need the "extra" stuff.   Exceptions which call for the "extras" would be on the rare side, and those cases will probably have a specific purpose or task to fulfill.  (eg growing pods to support a mandarin; a grow-out system; a breeder system; etc)

 

These days, folks don't tend to have that problem nearly as often as a tank that is persistently low on nutrients.  When you use all that "export power" on a tank that doesn't have excess nutrients, then you actually create a problem.  "Solutions looking for a problem."

 

[phinatic]

1 hour ago, mcarroll said:

Everything a filter pad would catch in a reef tank ought to be food for a fish, coral, another invert or microbe.

Fair point. I don't use it myself for the same reason. I use sponge filters to keep stuff out of the back chambers, but microscopic debris still makes it through.

 

1 hour ago, mcarroll said:

Last, the extra surface area puts excessive pressure on NO3 removal, among other things

I don't really see this as extra. The bacteria population is self regulating. If food decreases, so does the population. You're only providing extra area that they CAN colonize if the food supply dictates an increase. It also gives you a good way to colonize other tanks by pulling out a bag of media to seed the next tank full of dry rock.

 

1 hour ago, mcarroll said:

And what nutrients are considered "extra" since these are essential nutrients for our corals?

Similar to the last comment about bacteria, macro uptake is self regulating. As nutrients decrease, so does their growth rate. You can also examine the color/growth pattern to get clues about the state of the system. In my most recent tank I planted red graciliaria in the display and also placed it in the refugium. This was before any coral and other algae. It's helpful because you can see the flow patterns and it also seeded a huge pod population. I just fed my CUC and gave it time to build up. As I add coral, I can just remove the macro holding its place, either adding it the fuge or removing it for nutrient export.

 

1 hour ago, mcarroll said:

This much is fine.  But most folks don't leave it at pod farm/dark zone.

Macro works great for this. I didn't even seed my tank with pods. I just added some red macro and waited. With no fish in the tank, the population took off, covering every surface.

 

1 hour ago, mcarroll said:

Real reefs experience day/night pH changes

 

True, but the buffering effect of the ocean is huge. A contra-scheduled refugium provides a little buffer for a small volume of water that is typically packed much more densely than the ocean.

[mcarroll]

Remember, lack of need was the overall objection.  

 

If I'm starting a new tank, and it's just a regular reef tank, then I don't need "extras".  "KISS" theory, if you know the reference.

 

9 hours ago, phinatic said:

Fair point. I don't use it myself for the same reason. I use sponge filters to keep stuff out of the back chambers, but microscopic debris still makes it through.

That's a perfect example of the exceptions I was talking about that have very specific purposes to accomplish.

 

9 hours ago, phinatic said:

I don't really see this as extra. The bacteria population is self regulating. If food decreases, so does the population. You're only providing extra area that they CAN colonize if the food supply dictates an increase. It also gives you a good way to colonize other tanks by pulling out a bag of media to seed the next tank full of dry rock.

Again, I completely dig the pragmatic argument.  

 

If you regularly need to start up other tanks, then having extra bio-media can be helpful.  I'd choose something aragonite-based, or at least calcium-based if possible.

  

But the idea of self-regulation isn't quite right.  

 

They self-regulate toward survival!  🙂 Bacterial mats don't just die back when food supply wanes.

 

The idea that (eg) nitrifying bacteria die when there's no ammonia comes up in cycling threads fairly often.  I usually point to Dr Tim's FAQ since he seems to be a well regarded source of info and product: https://www.drtimsaquatics.com/products/one-and-only-live-nitrifying-bacteria/

Quote

A common misconception about bacteria in general is that they die if they are not fed.[....]

Click to read the whole thing if you want.  It's good!

 

The point is that the bacteria population eventually grows to cover every surface where nutrients go.  

 

And even if test kits read 0.00 ppm, we know there are still nutrient pulses happening in the tank when we feed.   It's the bacteria keeping those levels so low on the test kit, and they are persistently growing and spreading in the process.

 

Once grown, the population pretty much sticks around and becomes a permanent factor in the system's demand for N....actually reducing it to N2 and making it functionally useless as a nutrient, sometimes to the point that it leaves the system to become atmospheric nitrogen.  

 

To an extent, this is natural so why question it.  But a tank has different needs than a wild reef since the food supplies are so unlike each other.  N2 actually gets recycled on a wild reef much more than it will in a tank, for example.  Plus, food supplies are 100% more appropriate and almost 100% more abundant and available on a wild reef....so access to dissolved organic nutrients (eg ammonia and derivatives) isn't at quite the same priority as it is in our tanks.

 

By doubling or tripling the surface area for bacteria, you double or triple the processing capacity.  

 

Specifically the speed of processing.  

 

Larger bacterial populations will process nutrient pulses more quickly.  Processing those pulses more quickly makes nutrients (eg from feeding events) available to the system for less time.  In a fish-only system, that's a good thing.  In a reef tank, you are stealing from your corals...which have neither the spreading capability of algae nor the uptake capabilities of bacteria. 😉 

 

Bacteria's unique biology (surface area to body mass ratio, from what I gather) allows them to consume nutrients down to such low concentrations that higher organisms can become deprived in a competitive environment.

 

Why do any of that on a tank that doesn't even have excess nutrients to begin with?

 

9 hours ago, phinatic said:

Similar to the last comment about bacteria, macro uptake is self regulating. As nutrients decrease, so does their growth rate. You can also examine the color/growth pattern to get clues about the state of the system. In my most recent tank I planted red graciliaria in the display and also placed it in the refugium. This was before any coral and other algae. It's helpful because you can see the flow patterns and it also seeded a huge pod population. I just fed my CUC and gave it time to build up. As I add coral, I can just remove the macro holding its place, either adding it the fuge or removing it for nutrient export.

This is only true to a small degree, if at all in most cases.  

 

Common macros like Cheato (the most popular) are fast growing algae types.  True to form they either grow fast and furious, or they slowly die back and dissolve into the tank..  (Scout out some "where did my cheat go?" threads.)  These macros seem to operate on a boom and bust plan, where when they use available nutrients until gone, then they cut and run...probably releasing spore many times in the process so they can settle new areas  

 

Exceptions like Codium seem to prefer slow growth, and might tolerate inadequate (low-nutrient) conditions for longer or better.   It's not as common so not sure....haven't experimented as much with it myself.  All I could say is that Codium doesn't seem particularly hardy to me.

 

Both are unlike green hair type algae, which due to a variety of capabilities, operates just fine at almost any ambient nutrient level.  (Watch folks force nutrient levels to low for hair algae and see dino's bloom instead.  Green algae can go LOW....way lower than most corals or macro.)

 

Very cool on the use of Gracilaria!  Most folks don't have access to less common algae like Gracilaria, so most folks don't think about it unless they're specifically planning a "macro tank".  

 

9 hours ago, phinatic said:

Macro works great for this. I didn't even seed my tank with pods. I just added some red macro and waited. With no fish in the tank, the population took off, covering every surface.

Yes! 👍

 

All algae tend to harbor epiphyte populations including diatoms, dinos, pods, nematodes, bacteria, etc.  (The algae's "holobiont", more or less.)  

 

Similar to but different from what you'd get from a chunk of frag rock or a scoop of substrate...or adding a new coral.

 

Any of them are superior to packaged tank starters if you have access to them....but I'd prefer the one that's "more reefy" and "less algae-ish" if I had a choice.  

 

(Packaged products are great for when you have to start from scratch....no access.)

 

9 hours ago, phinatic said:

True, but the buffering effect of the ocean is huge. A contra-scheduled refugium provides a little buffer for a small volume of water that is typically packed much more densely than the ocean.

It's huge, but wild reefs still experience pH swings from night to day.  It's normal.

 

Peaking at around 8.1 during the day due to the maximal levels of photosynthesis using up CO2 from the water faster than it can be replaced from external sources.  

 

Falling to around 7.8 at night as CO2 levels normalize after demand ceases.

 

So, controlling pH isn't particularly natural.  And if you ask me it actually qualifies as "chasing pH". 😉 

 

For anyone considering this outside of purely experimental/learning reasons, I'd recommend reading Randy Holmes-Farley's "High pH and Low pH: Causes and Cures" articles.  

 

The main thing that's emphasized across both articles is how there's an acceptable range of pH.

 

IF someone chooses to run a lighted refugium (vs dark), the more significant benefit of opposed lighting is preventing pH spikes.

 

The refugium's daytime spike would otherwise overlap with the display's daytime spike as they BOTH make CO2 and other nutrients dip, making the effect even more pronounced (maybe double).  Not good.

 

On top of the nutrient concerns at play here, high pH causes ammonia to be more toxic, it causes abiotic carbonate precipitation, among other unwelcome effects.

 

So, it's not that refugiums or macro algae or whatever have no place.  (It's not personal!)  It's just that the core system is the core system...and if you need extras there should be a need.  If there is, then it usually isn't a problem.  

 

But when things get away from that and a macro algae refugium is added to a tank that already has no excess nutrients, it doesn't make sense logically AND it can cause problems for corals in the system.

[phinatic]

9 hours ago, mcarroll said:

The refugium's daytime spike would otherwise overlap with the display's daytime spike as they BOTH make CO2 and other nutrients dip, making the effect even more pronounced (maybe double).  Not good.

Thanks for the thorough reply. Lots of points to think about. To clarify on the night cycled refugium...

 

I have a 12 hour daylight cycle with a 2 hour ramp up and down, so 8 hours of peak lighting. The refugium has a 13 hour cycle that partially overlaps with the starting and ending ramps for daylight, so it is on as the tank is waking and sleeping. This was to cap those spikes you speak of.