Everytime return pump starts up corals slough tissue

[REEF SMAC]

So every time you turn on your return pump you have more white, dead, exposed skeleton, on your acros?

Are they sticking up out of the water when the pump is off?

 

[grcforce327]

Something is going on there. I've never experienced that.I don't turn my pump off though,I just shut the valve. I have bubbles when I reopen the valve,so I don't think that's the problem. During my water changes,I have some acros partially out of the water,and still no issue.