Polyps not extending fully?

[cpllongjk]

What causes polyps on sps not to extend fully?

My tank parameters are stable and good:
pH 7.9-8.0
Ca 420
dKh 6.5
Mg 1300
po4 0.03
no3 0.2-0.5
temp 77.5
SG 1.025

My green digi, orange digi, and my montis are fully extended but the millis and other sps are not. The polyps do come out at night but not what you should expect from millis. I have plenty of flow in the tank; (3) 6055s all with flow mods and all controlled via my apex to produce random flow in the tank.

If someone could help me out that would be awesome.

Thanks.

 

[JG1]

too much direct flow, something picking at the corals (angel fish), even lack of nutrients can cause the polyp not to fully extend

 

[cpllongjk]

Ok, i doubt its too much direct flow because the pumps are pointing at the glass. I have no fish that pick at corals. Its got to be lack of nutrients then. Thanks.

 

[Reef Bass]

AEFW and redbugs come to mind. Try turkey basting some of them and see if flatworms don't come flying off.

 

[sminker]

Your ALK is a little too low for my tastes. I like to keep mine at 8-9.

Also, dont be so sure about your livestock. Please post your entire fish and cleanup crew livestock.

How big are the colonies? Where are they placed in the tank? A picture of a full tank shot would be worth a thousand words.