Zoa frag in decline

I purchased three Zoa frags about two weeks ago. Two of the frags are doing well, but the third is losing polyps. I can't see any noticeable signs of pests or diseases. The frags all went through a FW dip. I've included a pic of when I first got the frag and a recent pic.

Then:

Now:

 

What are your params? how high are they up in the tank?

 

Ammonia 0
Nitrite 0
Nitrate 0
Phosphate 0
PH 8.2
dkh 11
Didn't check calcium today, but I dose daily and have been keeping it around 400
I don't have a magnesium test kit yet.
Salinity 1.022 I've been having difficulty getting an exact salinity measurement. Here is a thread explaining why.

9 1/2" from the surface. Lighting is 39 x 4 T5 with stock 10k and actinic bulbs. The fixture is 3" above the water.

 

Okay, Mag and Calc really arent a big problem when it comes to zoas..

But besides that everything else looks good, Zoas are the type of coral that you cant know what that specific frag likes until you move it around the tank in different flow and lighting..

I would go buy some coral dip and do another dip on it just to be sure that there are no there are no nudis on it and stuff....But if you just recently did the FW dip..Just try and move it to the bottom of the tank, leave it for a few days and see if its starts doing better, if not..Add some flow on it and move it up a little..

You Kinda just have to experiment with them a little.

 

I moved it a few inches lower in a spot that gets a little more flow. When I moved it there seem to be a bit of detritus coming from between the polyps and the mat looks dirty.

 

That definitely could be bothering the polyps..

Just keep it there for a few days and maybe it will open up some.

 

You can also try to GENTLY blow the frag off with a turkey baster. 8)
YOU CAN USE A POWER HEAD IN YOUR TANK JUST BE CAREFUL NOT TO BLAST IT TOO HARD. Sorry for the caps.

 

Using the turkey baster removed quite a bit more detritus.

 

Sometimes they get dirty and refuse to open. Just don't move them now and see if they make a come back. Zoas and Palys can be very different from each other as far as lighting and one kind might like more then another. Could take some time for them to fully open so be patient.Good luck.

 

Good call. They seem to be doing better. One of the closed polyps is opening. The spot they were in was low flow and seems to have some detritus settling there.