Acan issuses

[MTsquared]

Hey guys I have an IM NUVO 38 AIO running currently. I am in the process of setting up a Waterbox 130.4. I noticed the last week or so one of my ultra acans is dropping it’s polyps and parts of the skeleton are becoming visible. Some of the other acans are showing signs of tissue retreating and I am trying to fix this before it wipes them all out and I have nothing to transfer to the new tank. I did a water change last week and plan to do another in the next day or so. Here are the current tank parameters from a water test I did tonight. Please let me know what if any thoughts you have or recommendations. Thanks in advance.

Temp 78
Salinity 1.025
Calcium 440
Alkalinity 8
Phosphate 0-0.25 (was hard to tell but looked closer to 0)
Nitrate 20-40ppm (was also hard to tell but looked closer to 20)

I did have a sea hare die in the tank but that happened in the last day which is why I think nitrate and phosphate levels could be elevated. I immediately removed the sea hare when I noticed. The thing to know is this issue was ongoing prior to the sea hare dying.

 

[MohrReefs]

I'd probably do a water change and get those nutrients down a smidge.

 

[Snarky Shark]

Any light changes? What other fish do you have? I used to have flame angel that caused recession as it was picking at the acans.

 

[intricate_reefer]

Any algae growing around the skeleton? I would also get your phosphates in range Shoot for 0.05-0.1.

 

[intricate_reefer]

Feeding always helps as well, any meaty food should work well

 

[MTsquared]

Thanks guys. No major changes to lighting or fish. I am going to do a water change today and again next week to try to get things under control. Here are a few pics from last week.