Well a couple of things come to mind:
- If your corals (The Taodstools) are only a couple weeks old in your tank, you should leave them alone for now. Leathers can be just as finicky as many other corals... it could take weeks, or even months before they fully acclimate to their new envoronment. I wouldn't adjust the flow unless you truly think it will benefit them.
- How much are you feeding and when? Corals learn to open when the tank is fed. Most corals open up at night in nature, but most reefers feed at night... which teaches the corals to open during the day. This is but a very simple and generalized explanation.. there are tons of articles I invite you to read in reefkeeping magazine.
- Check around the coral to see if anything is slightly irritating it. You'd be surprised to see who or what is under these corals.
- Check your pH... may it's swinging a bit more than is comfortable between the night and day?
HTH