Update: I did a water change using RO water after my original post and when I returned from class the water clouded up again. I checked the water color and it was not green so I'm going to say bacterial bloom.
I did not move over the filter cartridge because I changed filters and the old one would not fit in the new one. Figured there would be enough bacteria on the wood, substrate and water. I guess not. Strange how it just bloomed out of nowhere though after having the water be clear for the first two weeks.
My fish do not seem bothered by this though...