Hammer coral turning grey

jawil99 · Jan 2, 2024

I have recently gotten back into the hobby after a 7-8 yeah hiatus, previously having a fish only tank. I have an IM sr80 with lps and softies. The tank has been set up since April 2023. I have a question regarding one of my hammer corals. I bought it as a peach/orange colored hammer around the end of November and in the last 2 weeks or so I’ve noticed a small portion of the hammer is losing the orange on the tips and is turning the colors of the polyp stalks (a brownish grey color). I don’t think this is bleaching but I’m new to corals so I could be wrong. I’m running two kessil a360x on 50% max intensity. I also had a green hammer next to it, but moved the green one up slightly to a spot with higher flow and higher light as well, so I don’t suspect the light is too much there. I originally had the orange hammer on the sand bed on a frag disk in really low flow. When I moved the hammer to its current spot I saw tissue recession on the side facing the rock (I think from too little flow). So I increased flow around the orange hammer in the new spot as much as I could without disturbing other corals and recession does not seem to have gotten worse. The green hammer was also receding in little flow and once moved recession stopped. Can flow impact the colors of a coral like this? The flow still isn’t great but gives a slight sway in the Polyps. The weird thing is the area where recession is, is
on the opposite side of where the color is fading so I don’t think they’re related. All corals except for two candy canes seems to be doing fine. Does anyone have experience with this?
Parameter:
- alk (sal): 10.9
-nitrate (salifert): 5-10
-po4 (hannah): .22
-calcium (sal): 420
-mag (sal): 1320
-salinity: 1.026

Macbalacano · Jan 3, 2024

From the pictures they look pretty good. Hammers can change slightly in colour over time as they acclimate to you tank conditions - lighting, flow, nutrients etc.

With lighting - I'd recommend getting a PAR meter or looking on here for other folks with the same light and similar tank dimensions / corals. There may also be a video on youtube (BRS did extensive PAR measurements on my lights - AI Prime 16HDs). This will help give you an idea if your lights are too much or too little based on their current settings and the hammers' placement in your tank.

For me, as long as the polyps are visibly moving its likely getting enough flow.

Your nitrates are good. Phosphates are a touch high, but I wouldn't worry too much with hammers on slightly higher phosphates. All other parameters look good too.

Could there be any inhabitant in the tank that might be bothering them?

You can also check for flatworms / eggs. I have definitely dealt with them many times over the years with my hammers/torches/octospawns.

jawil99 · Jan 3, 2024

Macbalacano said:
From the pictures they look pretty good. Hammers can change slightly in colour over time as they acclimate to you tank conditions - lighting, flow, nutrients etc.

With lighting - I'd recommend getting a PAR meter or looking on here for other folks with the same light and similar tank dimensions / corals. There may also be a video on youtube (BRS did extensive PAR measurements on my lights - AI Prime 16HDs). This will help give you an idea if your lights are too much or too little based on their current settings and the hammers' placement in your tank.

For me, as long as the polyps are visibly moving its likely getting enough flow.

Your nitrates are good. Phosphates are a touch high, but I wouldn't worry too much with hammers on slightly higher phosphates. All other parameters look good too.

Could there be any inhabitant in the tank that might be bothering them?

You can also check for flatworms / eggs. I have definitely dealt with them many times over the years with my hammers/torches/octospawns.

Thanks for the reply. I don’t believe anything is bothering them. I have 2 flasher wrasses, two halichoeres wrasses, two clowns, along with cleaner shrimp who occasionally poke around on them. I haven’t seen flatworms or eggs. I have seen one hitchhiker on the glass but it looked more like a slug. It was very small, pink, and had antennas/eye stalks on its head, so I don’t believe this to be a flatworm. I did use the brs video on kessils to set up my lights as best I could. I thought I could get by without a par meter, and so far, I am, but I think I will look at getting my hands on one soon because it would make things easier if I could rule out light as a problem with certainty. My alk did increase from 8.8 (where I want it) to 11.5 over the course of about two months for some unknown reason as I wasn’t dosing anything to the tank and my water change water is around 8 dkh. However this increase in alk happened before getting the hammers and all other corals in the system did not show signs of stress during this time. Since getting the hammers/torch/octo, alk has slowly fallen to 10.7-10.9 over the course of about 3 weeks. If light were not the problem, could this decrease in alk over this time be too much of a fluctuation? I figured since it’s dropping so slowly I can let it keep dropping until it gets back to my desired range (8.5-9). Is this the wrong approach and alk should not be left to decrease even if it is happening slowly?

Macbalacano · Jan 3, 2024

jawil99 said:
Thanks for the reply. I don’t believe anything is bothering them. I have 2 flasher wrasses, two halichoeres wrasses, two clowns, along with cleaner shrimp who occasionally poke around on them. I haven’t seen flatworms or eggs. I have seen one hitchhiker on the glass but it looked more like a slug. It was very small, pink, and had antennas/eye stalks on its head, so I don’t believe this to be a flatworm. I did use the brs video on kessils to set up my lights as best I could. I thought I could get by without a par meter, and so far, I am, but I think I will look at getting my hands on one soon because it would make things easier if I could rule out light as a problem with certainty. My alk did increase from 8.8 (where I want it) to 11.5 over the course of about two months for some unknown reason as I wasn’t dosing anything to the tank and my water change water is around 8 dkh. However this increase in alk happened before getting the hammers and all other corals in the system did not show signs of stress during this time. Since getting the hammers/torch/octo, alk has slowly fallen to 10.7-10.9 over the course of about 3 weeks. If light were not the problem, could this decrease in alk over this time be too much of a fluctuation? I figured since it’s dropping so slowly I can let it keep dropping until it gets back to my desired range (8.5-9). Is this the wrong approach and alk should not be left to decrease even if it is happening slowly?

I'm actually dealing with a pretty big Alk swing myself. I have mostly LPS and have 3 hammers and 1 octospawn. My Alk had dropped to 5.3 and bumped it up to 6.3 in one day and will be working to get it up through small water changes over the next 2 weeks.

Everything looks happy and open and colours look great.

Based on what I've seen on this forum over the years, Alk swings of under 1 dKh per day tends to be the maximum before you typically see adverse effects. Personally, I would aim for 0.5 dKh swing per day.

juarec0201 · Feb 18, 2024

Curious if yours colored up. I have 2 golds that are turning like yours. Phosphates .08 and nitrates 7-8. Don’t seem bothered other than color change.