I switched from DE to Fiber Clear last weekend. What I read on the manufacturer's website said it filters about 3X finer than DE, and expect rapid pressure rise after switching. The claims may be correct...
Other posts I searched mentioned that as well. Well, in 5 days my pressure has risen 2 psi. In the past, I gained about 1 psi/month. After all the rains and runoff, I had quite a lot of fine silt in the pool. But nothing extraordinary; no drifts forming. I stirred it up and brushed stuff towards the main drain yesterday. This morning the pool is as clear as it's ever been. I vacuumed up the big stuff today, mostly shingle grit. Still, not as bad as other times I've vacuumed.
If I remember, I'll go out tonight after dark and turn on the pool light and see how many floaters I see.
I will keep posting my observations on Fiber Clear here.
Now, to make it easier for others to search this later, when the board gets busy:
"fibre clear" fibreclear fiberclear cellulose