Phosphates and nitrate.

whats your alkalinity? friends 14gal biocube was not able to house zoanthids due to alk being too low regularly (small water volume, requires more waterchanges to keep the alk balanced or they have to dose to maintain it)

i dont see 10ppm killing zoanthids. fact this 14gal biocube is currently at 40ppm NO3 because of an issue she had. although the NO3 is on its way back down to 0 after fixing feeding schedule the zoanthids in the tank have remained fine. the fact that their alkalinity was dropping to 2 KH was causing the corals to regress and look very unhealthy and back up to 10 KH after a water change and within 24 hours thereafter the life of the corals start coming back.

granted that water change is also redosing alot of other supplements, but out of all things tested it was ALWAYS alkalinity causing grief.

 

I tried moving them up down right left. everything. the phosphates maybe the problem. I cant find the source though i dont over feed 2 times daily and i use RO/DI water.

alk is 3-4 meq.