Receding acan corals

[KaloraX]

i got this frag from my lfs about a month ago, it was a two-polyped acan and it was doing great, eating at night and all that. but over the last 2-3 days, it's started to recede and i can see white skeleton showing around the polyp. my tank's a 30g, i use coral pro salt mix, and i did a water change a few days ago, plus a deep clean of the sand. now the tank's showing some mini cycle signs, a bit of algae on the sand but not much. could it be from that?

just tested the water and everything looks normal, ph's 8.1, alk's 10.3, nitrates are between 5-10 which is normal for my tank. salinity's 1.024, temp's around 80 degrees. my led's aren't on full blast, and the coral frag's at the bottom of the tank on the sand bed. maybe i should move it under some rocks so it's in the shade?

any ideas what i should do? should i do a dip or just let it see if it'll recover on its own, maybe from the water change?

[Vyro9]

I'm no expert but I recently had some issues with an acan frag of mine. I think my problem was a combination of things - high nitrates, high phosphates, and high alkalinity, plus I had a peppermint shrimp that was causing some damage, too much light, and too much flow.

To get to the bottom of your issue, I think we need a bit more information and a decent picture would really help. Have you tried reducing the flow and light on your acan? Also, are you seeing any signs of pests? And how's the recession happening - is it affecting both polyps equally, and is it starting from the outside in or the inside out?

You might also want to check your calcium, alkalinity, and magnesium levels.