Hammer coral receding since purchase

[gooeypig]

I got this hammer a few months ago. Initially it was nice and fluffy but has since receded pretty harshly. I initially thought that the water might be too dirty so I stepped up the water changes. Then I read last week that they may prefer slightly dirty water and that I was probably throwing the alkalinity off so I'm switching to biweekly changes now. I've also reduced the lighting in case it's getting too much. The thing that's throwing me off is that it just grew two new heads in the last two weeks, from the two heads I bought it with. So clearly it's reasonably healthy but just not extending.

I got an ATO to try and keep the alkalinity constant and I've just been testing it out this week. Did some loads of fresh water with some eight four in it and the most recent one without. My feeling is that it is a pH/alkalinity issue because the swing from not including the pH buffer solution in this latest refill is quite large. I'd appreciate other suggestions on what it might be though.



Specific gravity: 1.023 - same

pH: 8.0 - down from 8.4 yesterday

Ammonia: 0ppm - same

Nitrite: 0ppm - same

Nitrate: 0ppm - same

Alkalinity: 8.7 - down from 9.0 two days ago, which was up from 8.8 two days before that

Calcium: 420ppm - same

Magnesium: 1200ppm - same

 

[Coralreefer1]

I would play around with water flow as it may be getting too much flow. They also do well with target feeding. Moderate lighting is best for Hammers as well as all of the other Euphyllia species of coral.

 

[reelreefguy69]

If its receeding and looking a little brown on the outside it could be that its not getting enough light or light is too week. I upgraded my lighting when i saw my hammer getting small and discolored. It is recovering well with better life showing.