Anyone else have an idea of
what could be causing this?

It might help if you post your parameters. pH, KH, nitrate, etc.

Is it possible that your cloudy water is actually the beginnings of green
water? Often, a slight green water problem looks whitish or milky. It's not
until the algae gets really bad that it starts to look green.


Leigh

http://www.fortunecity.com/lavender/halloween/881/