Zoas keep dying

[dtum]

My Zoas keep dying, all the older ones and the new ones I've recently added. Polyps start to close on by one and then fall off.

All other corals are doing great. Here are my measurements:

Temperature 78.5 F Mar 10
TDS 6.0 ppm Mar 10
Phosphate 0.1 ppm Mar 7
pH 8.0 pH Mar 7
Calcium 470.0 ppm Mar 7
Salinity 1.025 SG Mar 7
Alkalinity 6.5 dKH Mar 7
Nitrite 0.0 ppm Feb 28
Nitrate 0.0 ppm Feb 28
Ammonia 0.0 ppm Feb 28

Tank started early January.

[Yinzer]

What is your lighting and where are the zoas located, high or low? pH seems a little low also. If the tank was started early Jan, it's only 2 months old? Are you using RODI water?

[A. Grandis]

Your alk could be a little higher. Calcium it kinda high. Need the balance there...
People will need more info from you besides the params, flow and light.
Perhaps a picture of the affected colonies?
Could be so many things...

Grandis.

[dtum]

What is your lighting and where are the zoas located, high or low? pH seems a little low also. If the tank was started early Jan, it's only 2 months old? Are you using RODI water?

Yes, the tank is just over 2 months old. Other corals are doing fine, I got quite a few SPS as well.

Using RO water, no DI. My TDS for RO is 6.

Some zoas are on the bottom and they seem to be doing better than the ones up high. Lighting is JBJ Nanocube Advanced LED, so quite powerful LED (89 watts).

[A. Grandis]

Probably bacteria infection.
Lugo's treatment.

Grandis.

[cichlid9]

do you mean they fall off before your eyes? I added some peppermint shrimp once and started noticing polyps floating around my tank. Do you have asterina starfish?