It has been my experience that my GSP do like the higher flow areas. When I increased the flow to my colony they really have begun to grow. I was worried about them, like you, and just waited it out (after experimenting with the flow issue).
After remaining closed for about a week, they had a tremendous growth spurt. Now, every time they close up for a couple of days, they always have a growth increase.
So, now I don't worry about them when they close up fpr a few days. Just check that all else (parameters,etc) are in line and stable.
HTH