The cloudiness could be caused by salt, by precipitation, by a small bacterial bloom, or perhaps due to a chemical reaction to the solvents used to bond the PVC. It could even by from oils in the plumbing, the new pump and new skimmer.

It will pass. There's nothing there to fuel it, other than the stuff that comes in tap water. This is why we don't use it, because you don't know what's in it and we want to eliminated any unknowns to keep things controllable.