Some Zoas Declining

[Cincyreefer513]

I've had my tank going for almost 4 months now. It was bought established. I'm having issues with some of my zoas starting to melt away. Namely Cat Eyes Extreme, Utter Chaos, and Orange Oxides. Others such as Dragon Eyes and Pink Diamonds have really shrunken their polyps. All others are doing fine. Also, my lps, toadstool, and mushrooms are doing mostly fine. Growth with the majority of the corals have greatly slowed or stopped but they still look good. Parameters are below:

Temp 78
PH 8.2
Calcium 400-410
Alk 7.5-7.3
Mag 1450+
Phos 0.30s
Nitrates 5
Salinity 1.025-.026

I realize my phosphate is very high which could be the reason for the slow or non-existent growth in most corals.
I do change out carbon about every 3 weeks.
No pests have been found.

Any ideas?

 

[vetteguy53081]

Take a look at light and flow which should be moderate and your phosphate and mag is elevated
Add iodide to the water occasionally

 

[Cincyreefer513]

Take a look at light and flow which should be moderate and your phosphate and mag is elevated
Add iodide to the water occasionally

The zoas with the issues are in 80-140 PAR. With others in up to 190 PAR and doing well, I'm not sure if that's the problem.
Flow is lower as well. None of them are getting blasted.
I've been dosing to keep magnesium up for my hammers. Phosphate is the next thing I need to tackle and manage.
I have not tried iodide yet so maybe I need to look into that.
Most of the problem zoas have been in the tank around 3 months or so. Others that came in the same time are looking great.
The Cat Eyes melted a polyp over a month ago and just recently started losing more. The Orange Oxides just started this week. Pink Diamonds started shrinking maybe a month ago. None of this was sudden.

 

[vetteguy53081]

The zoas with the issues are in 80-140 PAR. With others in up to 190 PAR and doing well, I'm not sure if that's the problem.
Flow is lower as well. None of them are getting blasted.
I've been dosing to keep magnesium up for my hammers. Phosphate is the next thing I need to tackle and manage.
I have not tried iodide yet so maybe I need to look into that.
Most of the problem zoas have been in the tank around 3 months or so. Others that came in the same time are looking great.
The Cat Eyes melted a polyp over a month ago and just recently started losing more. The Orange Oxides just started this week. Pink Diamonds started shrinking maybe a month ago. None of this was sudden.

Try very slight increase

 

[Pkunk35]

Did you used to have low phosphate like in the 0.0x range? I’d bet it is at least part of the problem (high phosphate). Reason I say so is bc I believe I have had sensitive zoas melt when I’ve spiked my phos, but of course can’t be 100% sure

 

[Cincyreefer513]

Did you used to have low phosphate like in the 0.0x range? I’d bet it is at least part of the problem (high phosphate). Reason I say so is bc I believe I have had sensitive zoas melt when I’ve spiked my phos, but of course can’t be 100% sure

I'm not sure. I didn't have a phosphate test until roughly 2.5 months in so I've only been testing that for about 6 weeks now. I use a Hanna ULR. It has mostly been in the 0.30s, but I did have a 0.41 and 0.55 reading when I first got it. This could have been due to not performing the test correctly, however.