Are you moving the vac head very slowly so as not to stir up the water anymore than you have to? I think what you are experiencing is pretty common. It happens in my pool, too. I go as slowly as I can and the pool floor looks spotless, but once the water quiets down, I can then see some dirt resettling on the floor, especially in the lines created where the foam padding under the liner is taped at the seams. It isn't a lot, but I want it to be perfectly clean. Not gonna happen. But, as soon as we get in the pool, the little bit of dirt/dust gets kicked up into suspension and you can't see it.

Welcome to the Pool Forum, by the way!