Problems with Acropora corals

[Reef_do_piza]

Good morning, my friends—how’s it going? Could someone help me out? I’ve had these Acropora corals for about 2 months, and in the last few days, they’ve started to look like this. They actually grew this way.

HANNA
10/15/2026, Kh 7.8, Po4 0.15 and No3 8.0
Today Kh 7.6, Po4 0.08, No3 7.8

 

[Gumbies R Us]

How does everything else look in your tank?

What does your PAR look like?

Anything that could be bothering them?

Flow of your tank?

What are you using to test?

 

[Reef_do_piza]

How does everything else look in your tank?

What does your PAR look like?

Anything that could be bothering them?

Flow of your tank?

What are you using to test?

I haven’t taken any PAR measurements yet. I have 2 Radion XR30 G4 Pro units, 2 Forfish G2 Pro (Brazil) 110W fixtures, and 2 VorTech MP40s in a 120x70x50 cm (LxWxH) tank. I use Hanna test kits.

 

[painter1982]

What caused your po4 to drop in half? What’s your salinity measurements over time? Looks like Apitasia outbreak going on too.

 

[Reef_do_piza]

What caused your po4 to drop in half? What’s your salinity measurements over time? Looks like Apitasia outbreak going on too.

My nutrient levels have always been near zero; I only recently managed to raise them. I believe the drop in phosphate is due to the fact that I slightly reduced the amount of food I provide—I used to feed twice a week with a mix I put together, consisting of various fish foods, nori, clams, etc.—and I also upgraded to a larger protein skimmer, which is actually oversized for this aquarium. My salinity consistently stays between 1.025 and 1.026, as measured weekly.
Yes, I am having issues with *Aiptasia* (anemones), but I’ll be adding a filefish today to take care of that.

 

[painter1982]

What caused your po4 to drop in half? What’s your salinity measurements over time? Looks like Apitasia outbreak going on too.

My nutrient levels have always been near zero; I only recently managed to raise them. I believe the drop in phosphate is due to the fact that I slightly reduced the amount of food I provide—I used to feed twice a week with a mix I put together, consisting of various fish foods, nori, clams, etc.—and I also upgraded to a larger protein skimmer, which is actually oversized for this aquarium. My salinity consistently stays between 1.025 and 1.026, as measured weekly.
Yes, I am having issues with *Aiptasia* (anemones), but I’ll be adding a filefish today to take care of that.

I think your issue is likely due to parameters fluctuating. Salinity being one of them. Par could play a role too. But I’m no expert, there are some on R2R that will chime in.

 

[Reef_do_piza]

I think your issue is likely due to parameters fluctuating. Salinity being one of them. Par could play a role too. But I’m no expert, there are some on R2R that will chime in.

Could this fluctuation—between 1025 and 1026—be harmful, given how small it is? I’ve always kept it at 1026, but for the past two weeks, it’s been at 1025; it’s possible that my tester (Milwaukee) is out of calibration.

 

[exnisstech]

I would look more into the PO4 fluctuating. That was a pretty fast decrease and SPS often don't appreciate that. They don't seem to mind fast increases too much. I have chronically low N and P in my SPS tank and found dosing ammonium bicarb and sodium phophate works very well and is pretty simple to get the amounts dialed in. I never had any luck trying to use food to raise nutrients. I have a hunch coral reefs experience some slight salinty changes but I could be wrong.

 

[Reef_do_piza]

I would look more into the PO4 fluctuating. That was a pretty fast decrease and SPS often don't appreciate that. They don't seem to mind fast increases too much. I have chronically low N and P in my SPS tank and found dosing ammonium bicarb and sodium phophate works very well and is pretty simple to get the amounts dialed in. I never had any luck trying to use food to raise nutrients. I have a hunch coral reefs experience some slight salinty changes but I could be wrong.

I’ll look into it. I’ve been dosing N and P to raise their levels, but it’s been difficult to keep them under control.

 

[exnisstech]

I've been dosing ammonium bicarb to keep nitrate detectable and a diy phosphate using sodium phosphate. Once dialed in I'm getting very consistent test results and coral are thriving. I chronically low N and P for several years I've had to dose. I moved into another tank 4 months ago and that trend continues so I keep dosing. I used to dose a diy nitrate solution but see much better results from coral and test results are more consistent dosing ammonium vs dosing nitrate.

The tank I'm working with.

 

[slingfox]

My nutrient levels have always been near zero; I only recently managed to raise them. I believe the drop in phosphate is due to the fact that I slightly reduced the amount of food I provide—I used to feed twice a week with a mix I put together, consisting of various fish foods, nori, clams, etc.—and I also upgraded to a larger protein skimmer, which is actually oversized for this aquarium. My salinity consistently stays between 1.025 and 1.026, as measured weekly.
Yes, I am having issues with *Aiptasia* (anemones), but I’ll be adding a filefish today to take care of that.

For feeding, you’re now feeding twice a week with a smaller amount of food? I haven’t heard of any SPS folks feeding their tank only twice a week. Not sure if that results in material fluctuations on parameters during the interim period or not.

 

[Reef_do_piza]

I've been dosing ammonium bicarb to keep nitrate detectable and a diy phosphate using sodium phosphate. Once dialed in I'm getting very consistent test results and coral are thriving. I chronically low N and P for several years I've had to dose. I moved into another tank 4 months ago and that trend continues so I keep dosing. I used to dose a diy nitrate solution but see much better results from coral and test results are more consistent dosing ammonium vs dosing nitrate.

The tank I'm working with.

 

[Reef_do_piza]

I dose Colombo’s Nitrate Plus and Phosphate Plus; they raise the parameters effectively, but I haven’t yet managed to figure out the maintenance dosage

 

[exnisstech]

For feeding, you’re now feeding twice a week with a smaller amount of food? I haven’t heard of any SPS folks feeding their tank only twice a week. Not sure if that results in material fluctuations on parameters during the interim period or not.

I've never been a fan of starving fish to maintain nutrients. But I've also been able to keep elevated N and P with no algae concerns so I feed away.

Not sure why my SPS tank always runs at or near 0, I feed a mix of frozen, pellet, and flake 3-4times a day.

 

[Reef_do_piza]

For feeding, you’re now feeding twice a week with a smaller amount of food? I haven’t heard of any SPS folks feeding their tank only twice a week. Not sure if that results in material fluctuations on parameters during the interim period or not.

Actually, I only feed the corals twice a week. I think that feeding them daily causes too much of a change in N and P levels.

 

[Reef_do_piza]

Nunca fui fã de deixar os peixes passarem fome para manter os nutrientes. Mas também consigo manter níveis elevados de N e P sem problemas com algas, então posso alimentá-los à vontade.

Não sei por que meu aquário de SPS sempre fica com pH próximo de zero, mesmo eu alimentando meus corais com uma mistura de alimentos congelados, em grânulos e em flocos de 3 a 4 vezes por dia.

 

[painter1982]

I think your issue is likely due to parameters fluctuating. Salinity being one of them. Par could play a role too. But I’m no expert, there are some on R2R that will chime in.

Could this fluctuation—between 1025 and 1026—be harmful, given how small it is? I’ve always kept it at 1026, but for the past two weeks, it’s been at 1025; it’s possible that my tester (Milwaukee) is out of calibration.

I think it is a likely cause. I had a fluctuation a while back from my awc and a couple of my acro’s showed issues similar to yours.

 

[CoralWealth]

that small change in salinity will have no impact.

It looks almost like some of mine do when theyre getting blasted with a straight flow current on them.

Did they just randomly have this pale color or gradually over time?

What about pests? I have seen red bugs/white bugs cause damage that caused the coral to stress and look pale like this.

 

[exnisstech]

That's almost identical to my SPS tank with the exception of alk which I keep around 8 dkH . I aim for 5-10 nitrate and phosphate 0.03 - 0.1. I have a hunch some of my acros wouldn't appreciate the higher levels on my other tank.

 

[Reef_do_piza]

Essa pequena alteração na salinidade não terá impacto.

Parece muito com o que algumas das minhas ficam quando são atingidas por uma corrente elétrica direta.

Será que essa cor pálida surgiu aleatoriamente ou foi um processo gradual ao longo do tempo?

E quanto às pragas? Já vi insetos vermelhos/brancos causarem danos que estressaram o coral, deixando-o com essa aparência pálida.

gradual.

Não vi nenhuma praga; verifiquei com uma lupa.