Favia tissue recession issues and solutions

[darktide]

I'm dealing with some major tissue recession issues on my toxic pools favia, and I'm stumped. Thought it might be due to low lighting, but I'm not convinced. This three-headed frag has been in my tank for around 8 months now, and the green eyes have lost a lot of their color. I haven't checked my current nutrient levels, but I'm guessing they might be high - I've started doing two 25% water changes a week to try and get them under control. I'm running GFO and carbon in a reactor, and my lighting is an AI Vega Color.

[darktide]

Still stumped here, anyone got a clue what's going on with my favia?

[aquagem]

posting pics and sharing your water params would probably help you get some better advice.

[darktide]

Will have an update tomorrow, was gonna post some test results tonight but ended up doing a water change before I remembered.