cloudy water.....empty tank

My tank has been running for a week, just have the overflow and wet/dry filter running with no substrate/decoration or fish in it. Water was clear for a few days, now it's a cloudy white. Can this be bacteria in the water even if i have 0 bioload? Also, I had to do new plumbing on my sump, could new PVC cause something like this?

Just finished up some testing on the aquarium and I'm even more confused. Phosphate tested at 0, but now my PH seems to have risen from the tap 7.5 to around 8.0. Anyone have any ideas? Also I should add i didn't treat the water, just filled and wanted to test my plumbing, and my water does contain chloramines, maybe that causes some trouble?


Oh and thanks for the quick response, this forum is such a great wealth of info!