Dying Zoas

[Chrysus]

Hi all,

We have had this zoa rock for over a year, and in the past few months it has seen significant die off. We have dipped it in Revive twice and saw the demise of a large number of small brittle stars, but nothing else. The second time we made sure to pull all stars off of it. It has not fully reopened since, and that was on Sunday night. It was in my 25 gallon lagoon with a single Kessil a360we over it, and after the second dip was moved to my newer 40 gal. The 40 just has an assortment of freshwater LED’s on it for now, but the one directly over it is the same one it grew and thrived under in our old 10 gallon.

I’m thinking that the next step is to try a freshwater dip... Good idea? Anything else I should try or any other idea of what might be happening?

First picture was the 10 gallon when we first got it, second is the 25 gal at the beginning of August, and third is right now.

Thanks for any suggestions.

 

[Tuffyyyyy]

What light did you have over it for most of the growth?

 

[Chrysus]

The Kessil was on it for most of the time. It started dying back under it though.

 

[PDR]

What are your tank parameters? Has anything changed recently? Do you run any carbon or GFO?

 

[Chrysus]

Nothing has changed pretty much since it has been running, not running any carbon, GFO, or other chemical media. Just filter socks and some bio media.

Amm - 0
Nitrite - 0
Nitrate - <5
pH - 8.4
KH - 5 (has always been low)
Calci - 440
Salinity - 1.025
Temp - 78F

 

[PDR]

Nothing has changed pretty much since it has been running, not running any carbon, GFO, or other chemical media. Just filter socks and some bio media.

Amm - 0
Nitrite - 0
Nitrate - <5
pH - 8.4
KH - 5 (has always been low)
Calci - 440
Salinity - 1.025
Temp - 78F

That alk is pretty low, have you verified it with another test kit or a test from an LFS? I know you said it has always been low, but I would recommend getting it to at least NSW levels. You never know how chronically low alk could affect things over time. I would also run a small amount of carbon for a few days just in case there is some unknown toxin causing issues.

What is your current water change schedule?

 

[Chrysus]

I haven’t double checked the KH, the lfs uses the same kit but I think I have another KH kit at home, I’ll see if I can find it.

The zoa is in a new tank now so toxins wouldn’t be an issue anymore, parameters for that one are 0/0/10, 480 calc, 0 phosphates, pH 8.2, 7KH, temp 81, salinity 1.025, water changes 5gal once weekly.