Less coral extension

[AZBigJohn]

I have been battling a cyano outbreak on my sandbed, so I have been moving my powerheads around to try and increase flow near the bottom. My issue is I have an open brain, a frogspawn and a hammer coral on the bottom. The open brain is loving the extra flow; the frogspawn is dealing with it fine, but my hammer is not fully extending anymore. I have moved it backwards a little between my rocks to try and shield it a little, but it still is not extending. It still has great color, it just won't extend. You can see a picture below.

How detrimental is this to the coral?

[IMG][/IMG]

[Reefmedic79]

Is it withdrawn because of too much flow or too little?

Too much can be very detrimental, it will prevent the coral from feeding, both physically and through photosynthesis, and at very worse it can tear the tissue of the coral possible introducing pathogens for infection.

Too little is less likely to cause problems. As long as the coral is moving, then you should be ok. If this is the case the coral will adapt to the new conditions and fully inflate in time. If after a 3-4 days things still haven't improved, I would consider moving the coral someplace new.