Acros turning from green to dark purple

[Nickt516]

Has anyone experienced the green acros turning dark purple or starting to lose just green in general. Parameters are as follows
Nitrate 0
Phosphate 0.03
Alkalinity around 10
Magnesium 1400
Calcium in 390s
Ph 8.1-8.2

only in frag tank apart of 400 gallon system

 

[Timfish]

Corals may adjust flourescing and chromo protiens to deal with changes in nutrients, lighting spectrum/intensity, water flow as well as diseases or parasites. I'd suggest looking at what has changes the last few months or if these corals are new to your system try to find out the conditions they grew in and comopare to your system. (FWIW your PO4 is at the limit identifed by research at SOuthampton University as teh minimum to prevent a phosphate deficiency, I would try to keep it a little higher.)

 

[Waters]

Unfortunately you have close to 0 (if not 0) nutrients with higher ALK. I would get some coral food into the system asap.