what kind of flow is it in? Is sand accumulating on the purple mat? IME the three times I got GSP before getting rid of it again it took about 3 days to open up fully, but thrived in a variety of conditions. The best thing you could do is find a good spot with decent flow and leave it alone.
I would maybe put it in higher flow if stuff is settling on it. I have had mine right in front of a powerhead that did great... they can handle it. I have also had it in low flow that did great. When I put it in too low of flow that detritus could settle on it that is when it became upset and wouldn't open like it should.