is this friend or foe?

[Pharmer Dan]

Tank 1 yr old stable pH alk, salnity, ca++, P04 nitrates very low. For some reason I haven't had any luck with zooanthids, have a colony of 20 or so polyps about 6 weeks old, slowly dying off, I dipped today and this critter came off the colony. Brittle star? Maybe it was hassling my zoos?

 

[Pife]

What are your parameters? What type of light do you have? Where are your zoanthids in the tank? What type of flow do you have? That looks like a harmless brittle starfish to me.

 

[saltyair]

+1 harmless brittle star

 

[Pharmer Dan]

Reefbreeder, max out at 30 on whites. LED 90 gallon. 30 gallon sump, Vertex 150 skimmer, Running GFO and Carbon. BRS 2part. Neputne APEX to run BRS 2part, 2 Koralia 1500gph on a koralia wave pump and one Koralia 240 GPH near the surface runs constantly.

pH 8.15 (very stable)
Temp 78-80 controlled by APEX
Salinity 1.025
Nitrate 4-12 ppm
P04 0.5ppm
ALK 151 ppm
Ca++ 145-150ppm
Mg 13-1400ppm

Ive tried a few locations, top middle, bottom, med flow. I thought it was a brittle star too, just hoping Id found something to blame my lack of growth on
Of note I have a few mushrooms that are a year old, very healthy but never spread, a healthy chung of Xenia that also has not spread.

 

[Pife]

I would try and shade them some. If your Ca results are right that's super low. Do you know what the conversion of alk is to DKH? My guess would be to much light. Do you happen to know the par where you are putting them. What other corals are you growing/dying?

 

[Pharmer Dan]

Oops Ca ++ 400
ALK converts to 8 DKH
Nothing other than green start polyps really seem to take off and grow, I have a blastomussa merletti that is doing well, slow growing, One duncan doing well, slow growing. 1 year old fluorescent green toadstool that has good color but size of a nickel still. Tried ACANs x 2 they didn't last. Right now my 3 bubble tips, Rose, orange and Green are the stars of my non fish inhabitants

 

[Piper27]

.5 is a little high for phosphates, I have had bad experiences with corals at that range, unless you meant, .05...

 

[Pharmer Dan]

damn yes P04 0.05