SPS Healthy & Colorful but Not Growing, Zoas Partially Closed - Ca, Mg, Alk Barely Decline. Why?

[sgrosenb]

Hi folks,

I've finally gotten my tank to a point where my SPS don't die... which is great! You can read about my prior tank woes here if interested...

However, I don't want my SPS to just not die... I'd like them to grow! I have about 20 different SPS frags, each roughly 1" inch long or so. The absolute best growth I've had is from my Blue Lightning Stag, which has grown by about 1/4 inch in the last few months (pics below) and my Snow Cap monti. Most other frags have not grown at all.

Below are all my parameters. I'm trying to figure out why my Ca, Mg and Alk basically do not decline on their own (Alk does veryyyy slowwlllyyyy sometimes, but when I do a small dose of Soda Ash, it bumps back up and stays level for a week or two before declining again). I would think that, given that the tank has some SPS and LPS in it, that there should be a pull on at least calcium... but there doesn't appear to be. I feel like there must be some piece to the puzzle that I'm missing that is causing my corals to not grow and resource not to be pulled on. Any help would be greatly appreciated!

Tank Parameters:

• Alk: 8.3
• Ca: ~480
• Mg: ~1290
• NO3: 8ppm
• PO4: .08ppm
• Salinity: 1.026 (I use Tropic Marin Pro Reef Salt; weekly 10% water changes). I've tested the replacement water with Triton - it is 7.1dKH, 490 cal, 1310 Mag.
• Lighting: Hybrid LED/T5 Combo. 4x T5 ATI Blue Plus running 10am-6pm. 3x Radion XR15 G4 Pro running SPS AB+ 10am-6pm with a short ramp up/down. I run the Blue/Royal Blue spectrums at roughly 5% from 6pm-10pm and 5am-10am. PAR measures around 250-350 for my SPS, lower for LPS (see PAR picture below).
• For flow I have 2 Maxpect XF 250 Gyres running anywhere from 20-40% at any given time.
• Return pump is Vectra L1 at roughly 50% power
• Bubbleking Mini 160 protein skimmer running 24/7
• Refugium completely full of chaeto. H380 Kessil light on 8 hours at night over fuge.
• No algae issues in display tank
• No filter socks. Roughly a 1/8" of detritus at the bottom of my refugium.
• pH ranges from 8.0-8.3 like clockwork throughout the day
• Temp goes from 78.0-79.0 each day (added a chiller a few months back)
• Auto top-off 4-stage Spectrapure RODI. Registers 0 TDS consistently. My tank is pretty far away from my RODI so I have about 50 feet of tubing that runs to the tank. I flush the RO system for 5 minutes every time before adding fresh water so that I don’t get TDS creep
• Dosing – I have dosed very little over the past 6 months. A little Amino Acids here and there, some Phosphat-E to keep PO4 in check (I recently stopped that since Lanthanum was showing in an ICP test - see link to most recent ICP test) and then a tiny bit of Soda Ash when alk declines. There's really not much else. Never dosed calcium, and I dosed a tiny bit magnesium a few months back.
• Coralline Algae – There is a good bit on my two gyres and my magnetic glass cleaner. There’s also some on my rocks and glass, but it’s not caked on there like I see in a lot of tanks. Not sure why it hasn’t taken off yet – might be another hint as to why SPS won’t grow.
• Other corals – I have a few zoas and hammers that I have had for over 6 months. The Zoas are doing fine and are colorful, but they're not fully opening and aren't really reproducing like I've seen in other tanks. Maybe another clue as to what’s wrong with my tank?
• Fish – I have a bunch of fish in there – probably 15 or so. All happy and healthy. I did add a Coral Beauty angel recently, but I watch my tank a lot and have never seen him nip at corals.
• Food feeding (fish): PE Pellets 3x daily; PE mysis shrimp 1x daily (2-3 cubes)
• Food feeding (coral): I add in ReefRoids every week or two. If I use it too heavily, it seems like phosphates get too high.
• Absolutely no sign of pests that I can see
• Most recent ICP test here: https://www.triton-lab.de/en/showroom/icp-oes/109548

Here's a few charts of my params:

Trident readings (ignore the dip - I tested my replacement water change water)

KH Director:

PAR Readings:

Lighting Settings:

Coral Picture Example of coral that is growing the fastest out of them all:

Taken June 16, 2020:

Taken July 16, 2020:

Snow Cap Monti taken May 15, 2020:

Snow Cap taken July 16, 2020:

Example of no growth:

PC Rainbow taken June 16, 2020 vs July 16 2020:

 

[Randy Holmes-Farley]

I'm not sure why they are growing slowly and hence using little alk, calcium, and magnesium.

 

[dragon99]

Sounds like you are doing everything correctly and have parameters inline. Keep those steady and you should see improvement.

My only suggestion would be to increase flow. 40% on the gyres seems pretty low.

 

[sgrosenb]

Dang... if I stumped @Randy Holmes-Farley then that is not a good sign... Thanks for the note @dragon99 . Does the lack of uptake of Ca, Mg and Alk concern you at all? I feel like there has to be something in the thank that is causing alk to stay stable (it used to RISE... but I replaced all the rock and so now it at least stays stable rather than rising), and stunting the growth of the corals. If I really boil it down, the only meaningful thing I'm adding to the tank on a daily basis is RODI water and fish food. Seems like it's either one of those two, or something in the tank. RODI water continues to test perfectly...

 

[dragon99]

Alk, Ca, Mg not dropping is exactly what I'd expect if you aren't seeing much growth. They will only start to decline when the corals grow. Water changes are likely replenishing some of those elements even if you aren't dosing.

 

[Larry L]

My only suggestion would be to increase flow. 40% on the gyres seems pretty low.

I agree, I'm running two of the xf230's on a three-foot long tank, and have them alternating every hour from 100%/10% to 10%/100%. Plus another Sicce powerhead in the back corner to help keep detritus stirred up.

You might also want to try extending your lighting period by an hour or two and see if that makes any difference.

 

[Xanthurum]

Everything looks good to me, it appears that they are all fairly new frags and still in the encrusting phase so to speak. New frags will encrust for sometimes a very long time prior to showing vertical growth. During this phase they do not consume much in the way of Alk or Calcium since they are still relatively small. Plus you are doing weekly water changes so you wont see much change in parameters, which is a good thing. Keep doing what you are doing and soon you will see vertical growth, be ready to test often to keep things stable.

 

[HuduVudu]

Did you do anything to bring biodiversity to your tank?

 

[sgrosenb]

@HuduVudu I have a large cleanup crew and I add in about 100lbs of 100% live rock. Live rock has sponges, crabs, cucumbers, feather dusters, etc. Is that what you're referring to?

 

[HuduVudu]

@HuduVudu I have a large cleanup crew and I add in about 100lbs of 100% live rock. Live rock has sponges, crabs, cucumbers, feather dusters, etc. Is that what you're referring to?

When did you do it? And yes

 

[sgrosenb]

When did you do it? And yes

Cool! I put roughly 40lbs of live rock from Tampa Bay Saltwater in March 2020, and then another 60lbs from KP Aquatics in May. I started my tank in Nov 2018, but as you can see in my "problem" linked thread, I had a lot of trouble with the tank from Nov 2018-March 2020 when I started putting live rock in. So I'd say the really bio-diverse stuff has been in there for about 2-4 months.

 

[HuduVudu]

Cool! I put roughly 40lbs of live rock from Tampa Bay Saltwater in March 2020, and then another 60lbs from KP Aquatics in May. I started my tank in Nov 2018, but as you can see in my "problem" linked thread, I had a lot of trouble with the tank from Nov 2018-March 2020 when I started putting live rock in. So I'd say the really bio-diverse stuff has been in there for about 2-4 months.

@sgrosenb I read your other thread. I find your problem to be interesting.

I have some weird questions, bear with me if you like. I see that you are in FL. I am in TX ... howdy. I have been running my AC for quite some time now. I am assuming this is true for you also, correct? When was the last time that you aired out your house? Do you do this regularly? Do you have a outside air input to your skimmer? Does your AC exchange air with the outside, if so how often?

Before I started paying attention to gas exchange around the tank i.e. the house. During the extremes of the year I tend to keep my house closed and running some form of temp adjustment. This can cause a build up of CO2 and a decrease of O2 in the house and this will ultimately affect the tank. You said that in your other post that you had a bunch of fish, do you still have them? What are they? Your PH swing does seem correct and your fish seem fine, but if you have a low enough fish load and high enough Alk (which you do) then things might seem normal even if you have elevated CO2. Do you have a PH probe on your tank? I am assuming you do but I want to be sure. If you do is it possible for you to open a window near your tank and use a fan to move air toward your tank for a few hours, perhaps in the morning when it is cooler. If you can do that you should watch your PH change and see what happens. If it follows it's normal course then I am leading you down a dead end. If it does not then you have a gas exchange problem at the house level.

One of the problems that I have found is that there is no way to test for actual alkalinity using the tests that are available to aquarists. We get bicarbonate and carbonate and we can't tell how much of each we might have. Bicarbonate is illusory and can go back to CO2 quickly making it unavailable, thus making it hard to determine exactly what our Alk is.

Just some ideas. I feel your pain, it sux when things don't make sense.

 

[sgrosenb]

This is great - thanks @HuduVudu I am open to ALL theories at this point; as you said, it just doesn't make sense. Before I get into pH below, a few notes to consider as we problem solve:

• When I first set up my tank, I used Dr. Tim's one and only to get it up and running. It cycled, and then was doing pretty well. Maybe 6 months in, probably April 2019 or so, my alkalinity was declining on its own and I added some SPS corals and they took off. They did great - grew fast, good colors, etc. That lasted for maybe a month or two, and then they died. I think that's about the same time that my alkalinity started to increase on its own rather than decrease. The only thing I dosed during that time for alk was the Soda Ash from BRS.
• When I first removed all my rock and most of my sand a few months back in March 2020, my alkalinity started to decline on it's own. When it first declined from roughly 10.0 to 7.5, I added some Soda Ash to get it back up to 8.0. It sat at 8.0 for a few weeks, and then began to decline again. I then dosed a bit more Soda Ash (20ml) and got it up to 8.0. The 20ml dosing was a few weeks ago. Since then, alk has been flat or actually slightly increasing according to my Trident. This just seems odd to me and feels like it likely plays into my problem. Something is causing that alk to increase and I cannot figure out what it is (unless the readings are inaccurate as you stated. I'm not smart enough to know the details on that!).

Back to your questions:
In terms of fish - I have about 15 fish in there (tang, angel, 5 damsels, 3 anthias, 2 clowns, 2 hawkfish, a cardinalfish, a firefish. They are all very happy and eating well. No issues with them whatsoever.

I can certainly open my windows one morning and give this a try. Can you give me an idea of what I should be looking for? I have a pH probe in my tank. Below are a few charts - you can see on any given week it fluctuates between 8.0-8.3. When my family leaves the house for vacation (there are 5 of us and a dog), you can see a noticeable increase in pH while we are gone. Conversely, when we have people over to the house, pH drops (see yesterday's 7/19/2020 pH that only got up to 8.15 - we had about 5 extra people yesterday.)

Recent normal pH reading (with more people at the house on 7/19):

Readings when we are not at the house:

Thanks again for all of your help. I have put so much time, effort, energy and passion into this and all I want is for my SPS to thrive!

-Scott

 

[Perry]

BRS makes an inline CO2 scrubber, this would be my next play. All looks great, and if you are at a crossroad, a rather inexpensive addition may be worth the cost. There is a possibility that you may see an increase in alk consumption, thus the need to dose. A suggestion to read up on and possibly employ, FWIW
Cheers

 

[EMeyer]

Am I reading this correctly that you're expecting visible growth within a month (June vs July 2020)?

In my experience, Acros don't grow when you first add them to the tank. They spend a month deciding whether to die or not. Then the second month doing a little encrusting. Somewhere in the 2nd or 3rd month they start growing at a normal rate, and continue thereafter. That has been my experience with pretty much every Acro I've added to a tank.

Two of your corals show visible growth in a month... I'd start taking pictures at 1 month intervals and reserve judgement til they've been in place 6 months.

 

[sgrosenb]

BRS makes an inline CO2 scrubber, this would be my next play. All looks great, and if you are at a crossroad, a rather inexpensive addition may be worth the cost. There is a possibility that you may see an increase in alk consumption, thus the need to dose. A suggestion to read up on and possibly employ, FWIW
Cheers

Thanks @Perry for the suggestion. I did some quick research (will read much more) and it seems like people often use these to increase their pH. Given that mine is fairly consistent at 8.0-8.3, could you expand on what the CO2 scrubber would do for the tank? I haven't heard this suggestion yet and am certainly game to try it. Just want to learn more about it. Thanks so much.

 

[sgrosenb]

Am I reading this correctly that you're expecting visible growth within a month (June vs July 2020)?

In my experience, Acros don't grow when you first add them to the tank. They spend a month deciding whether to die or not. Then the second month doing a little encrusting. Somewhere in the 2nd or 3rd month they start growing at a normal rate, and continue thereafter. That has been my experience with pretty much every Acro I've added to a tank.

Two of your corals show visible growth in a month... I'd start taking pictures at 1 month intervals and reserve judgement til they've been in place 6 months.

Thanks @EMeyer - I've had most of these corals in the tank since June 2nd, so it's been about 7 weeks. I would love it if it was just a matter of time before they took off, but I haven't seen that yet for any of the 20+ corals. The most growth I've had is from my Snow Cap monti (the only coral that managed to make it through from my last batch that I tried to grow about a year ago) - you can see in the pictures how much growth there was in 2 months. I'm also not sure it explains my zoas not opening and my alk rise. Any thoughts on those?

 

[Perry]

Thanks @Perry for the suggestion. I did some quick research (will read much more) and it seems like people often use these to increase their pH. Given that mine is fairly consistent at 8.0-8.3, could you expand on what the CO2 scrubber would do for the tank? I haven't heard this suggestion yet and am certainly game to try it. Just want to learn more about it. Thanks so much.

I think by scrubbing CO2 from system, you may find a kick start in uptake, I have personally noticed just that. I have seen coraline algae take off, and dosing mainly more alk, which also stabilizes ph. In my home, FL, AC non-stop, and tank is in a common living area, family of 4, 2 small dogs, small livingroom, almost a must for my situation. Drawing fresh air would be my preference, but not doable where tank is. @120reefkeeper has a nice write up about this, FWIW
All the best, otherwise, TIME, once corals lay there base, then growth takes off.
Cheers

 

[HuduVudu]

@sgrosenb as I suspected.

So, some basic chemistry first.

CO2 goes into solution and when it's concentration gets high enough it starts to form carbonic acid (H2CO3). This then goes further to form bicarbonate (HCO3-). This can all be found here: https://en.wikipedia.org/wiki/Carbonic_acid

This reaction can go forward and backward. This is the same premise that Calcium Reactors are based on. When you increase the CO2 around your tank you will create more acid as described above thus driving the PH down. The interesting tricky part is that the zooxanthellae in the coral tissue that are responsible for energy production require CO2 as they are a plant, but there is a secondary mechanism that is responsible for calcification (which I am not as clear on) that requires CO3 for skeletal growth.

As I mentioned before Alk tests aren't as they seem. You measure both CO3 (needed) and HCO3- (illusory). The interesting thing is that if you use a base you can bind out the acid (H-) into water and then your illusory bicarbonate becomes needed carbonate which is usable by the corals.

I also want to point out too, when you dose soda ash (NaCO3) you are indeed dosing CO3 but you are also dosing Na into your tank. Doing this is going to throw off your NaCl (salt) balance. This balance is essential to maintain in a salt water aquarium. Because we have to send out water samples to get balance numbers this makes keeping NaCl in the proper balance important. That said when you dose you must dose both CaCl and NaCO3. Even this over time will cause problems for two reasons; first the keeping the balance between the Na and the Cl is difficult because of the consumption of CO3 by the biological filter, second the Na and the Cl concentration will become greater in the solution because the Ca and CO3 are being consumed. Read up on Balling method for details on this mechanism. I don't believe that our machines can truly keep these balanced correctly. That is why if you are dosing it is imperative that you water change. I don't know how long or how much you were dosing in the beginning, but if enough it could have thrown your water chemistry. It is good that you do water changes perhaps you might want to up them a bit to get any imbalances corrected. Note: I can't understand why Triton doesn't test for Cl this is strange to me. ATI does FYI.

So what to do. Leave your house all the time so your PH stays stable Seriously though work on the CO2 issue. @Perry suggestion is one possibility but be warned human beings produce a ton of CO2 and you also need to keep up on the media. Also remember CO2 scrubbers do not produce O2 so those levels need to be dealt with. It seems your tank load is low enough to not tax O2 so that is good. Be warned though low O2 levels bring up the odds of tank diseases, and if you add more fish be very watchful for this phenomena. I personally air my house out twice a day in the extreme temperature parts of the seasons and leave the windows open when the season permits. I am working on plant based solution because it turns out the LED revolution has made grow lights extremely cheap and efficient. Here is a calculator for turn over for room CO2: https://www.engineeringtoolbox.com/pollution-concentration-rooms-d_692.html I also suggest that for now you use kalkwasser as your alk/calcium solution. It is balanced and won't add extra ions that cause balance issues. In time however your tank will out strip the kalkwasser and you will need to decide between dosing and a reactor. Each has it's own pitfalls and you will have to work with your choice on those pitfalls.

I hope that this can bring some clarity to the problem that you are having.

 

[Perry]

@sgrosenb as I suspected.

So, some basic chemistry first.

CO2 goes into solution and when it's concentration gets high enough it starts to form carbonic acid (H2CO3). This then goes further to form bicarbonate (HCO3-). This can all be found here: https://en.wikipedia.org/wiki/Carbonic_acid

This reaction can go forward and backward. This is the same premise that Calcium Reactors are based on. When you increase the CO2 around your tank you will create more acid as described above thus driving the PH down. The interesting tricky part is that the zooxanthellae in the coral tissue that are responsible for energy production require CO2 as they are a plant, but there is a secondary mechanism that is responsible for calcification (which I am not as clear on) that requires CO3 for skeletal growth.

As I mentioned before Alk tests aren't as they seem. You measure both CO3 (needed) and HCO3- (illusory). The interesting thing is that if you use a base you can bind out the acid (H-) into water and then your illusory bicarbonate becomes needed carbonate which is usable by the corals.

I also want to point out too, when you dose soda ash (NaCO3) you are indeed dosing CO3 but you are also dosing Na into your tank. Doing this is going to throw off your NaCl (salt) balance. This balance is essential to maintain in a salt water aquarium. Because we have to send out water samples to get balance numbers this makes keeping NaCl in the proper balance important. That said when you dose you must dose both CaCl and NaCO3. Even this over time will cause problems for two reasons; first the keeping the balance between the Na and the Cl is difficult because of the consumption of CO3 by the biological filter, second the Na and the Cl concentration will become greater in the solution because the Ca and CO3 are being consumed. Read up on Balling method for details on this mechanism. I don't believe that our machines can truly keep these balanced correctly. That is why if you are dosing it is imperative that you water change. I don't know how long or how much you were dosing in the beginning, but if enough it could have thrown your water chemistry. It is good that you do water changes perhaps you might want to up them a bit to get any imbalances corrected. Note: I can't understand why Triton doesn't test for Cl this is strange to me. ATI does FYI.

So what to do. Leave your house all the time so your PH stays stable Seriously though work on the CO2 issue. @Perry suggestion is one possibility but be warned human beings produce a ton of CO2 and you also need to keep up on the media. Also remember CO2 scrubbers do not produce O2 so those levels need to be dealt with. It seems your tank load is low enough to not tax O2 so that is good. Be warned though low O2 levels bring up the odds of tank diseases, and if you add more fish be very watchful for this phenomena. I personally air my house out twice a day in the extreme temperature parts of the seasons and leave the windows open when the season permits. I am working on plant based solution because it turns out the LED revolution has made grow lights extremely cheap and efficient. Here is a calculator for turn over for room CO2: https://www.engineeringtoolbox.com/pollution-concentration-rooms-d_692.html I also suggest that for now you use kalkwasser as your alk/calcium solution. It is balanced and won't add extra ions that cause balance issues. In time however your tank will out strip the kalkwasser and you will need to decide between dosing and a reactor. Each has it's own pitfalls and you will have to work with your choice on those pitfalls.

I hope that this can bring some clarity to the problem that you are having.

Yes true..
I have a refugium, and grow mangroves in DT, I too want to liven up the living area with plants, especially air purifiers like spider plants. I doubt I need to run Scrubber, but have not seen ill effects, likely my marine plants are producing plenty of O2. My fuge harbors prolifera and mexicana caulerpa which grows like crazy.