Hammer Coral Tissue Recession

LikeRichMahogany · Jan 4, 2025

I have a garden of 9 different varieties of hammers, and they have all been growing, sprouting new heads and splitting, and I’ve seen the polyp extension really take off. My purple and green hammer coral however in particular receding almost completely approximately 3-4 days ago. It was open and healthy, and had recovered completely when I rescued it from a tank tear down 6 months ago.

The rest of the hammers are open, healthy and happy and are all under similar lighting conditions.

I’m not currently dosing, but about to start all for reef.

My alkalinity is at 6.7 and my calcium at 395.
My nitrates are at 0.1 and my phosphates are at 0.2 currently (not 0.02), due to them leaving out of the 25 year old live rock I have.

Could these less than ideal parameters be causing the recession is does it seem something else could be at play? I worry a little about euphyllia eating flatworms, considering the proximity of this coral to my other hammers

crazyfishmom · Jan 4, 2025

Alkalinity at 6.7, if consistent, is not a big deal. Keeping at 7-7.5 would be better though. If you raise alkalinity a little, you’ll also raise calcium and that will be in better range so no worried there either.

Nitrates being that low is concerning. I would either dose a little ammonia or something like neonitro to get them consistently into the 5-10 ppm range.