HELP with umbrella leather!

Hey guys, I've got a 7" umbrella leather with three heads on it. The problem that I'm having with it is that it will look amazing for a couple of days, then it will shrink, and turn a greyish color for a couple more, then look good for a couple more days, and so on.

I've also got a colt coral, and it does about the same. The thing is, that they seem to alternate back and forth, looking good, then bad, It's really weirding me out.

My setup:

55 gal

23 gal fuge

seaclone 100 skimmer

rena xp2

1 koralia 150gph PH

1 maxijet 1500 w/koralia conversion

DIY LED

80lb live rock

My parameters:

Temp 79.5

SG: 1.023

Ammonia:0

Nitrate:0-5

Nitrite:0

PH:8.2

Calcium:480

KH:13

Phosphate:0

My stock list:

1 Big maroon clown

2 Blue sided fairy wrasses

1 Flame angel

1 Pink spot goby

15-20 snails

10 small hermit crabs

1 big purple tip sebae anenome

1 colt coral

1 umbrella leather

10 green mushrooms

I've tested for everything, and can't seem to find anything wrong. I haven't  seen anybody nipping at any corals, My mushrooms look amazing, I just can't think of anything that could be wrong.

Here's some pictures

Will colt corals and Umbrellas harm each other? It seems that when one is looking good, the other looks crappy. This is the only thing I can think of as to why they look bad.