I returned from a trip to the petstore after work as I had my eye on one of their new adult angelfish in stock. After returning home with my new angelfish I noticed my tank has a slight cloudiness about it. I can still see the fish and plants clear enough but it looks like I dropped a few spoonfuls of milk in there. I did a gravel vacuuming and water change last night, water was nice and clear. I only feed my fish once every three days. Half a pinch of flake food for my one angel (at the time) six sinking pellets for the 6 corys, and the occasional blood worm or two as a treat. I checked my water parameters with my test strips and they came back safe. Any ideas?