Hammer Coral Not Looking Good

[407_Reefer]

Got a 2 hammers 4 months ago or so and they slowly has been looking worse and worse. I have 2 others that I got around the same time that look great. Anybody have any idea what the issue could be with these 2 guys?

Thanks!

Alk 8.3
Phos .16
Nitrate 6.2
Mag & cal are great

 

[407_Reefer]

The second pic is before first is after

 

[spielco]

For the mag being great What is great? How is the flow around him?

 

[Matt Bravo]

I agree that problem could be flow. Hammers don’t like too much flow and will start receding if it’s too much. But I do notice that maybe it’s splitting?

 

[rsmbudgetbuild2024]

What is your calcium at exactly? I am starting a new tank too and at 360-370ppm approx. and I dose ionic calcium every 1-2 days and my large hammer colony will visibly close down, secrete a bit, but then eventually will open back up when it detects the calcium ions around it. It bothers it for sure but I am dosing for its own good.

calcium is super important for growth of healthy corals and you ideally want your calcium at 430-460ppm in your tank. I am using Reef Advantage Calcium by seachem (better than their original/non-Advantage formulation from my understanding) as it doses in ionic form and also is dosing for Mag and Strontium too which is nice and according to some equally or more important than calcium.