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Be careful. Go here [where the OP had an algae bloom caused by high nitrates and too much light] and read my post #11:
http://www.aquariumadvice.com/forums/f12/water-cloudiness-336239-2.html
Once your tank is fully established (say in another month or two), don't skimp on gravel vacuums unless your tank is fully planted and the plants are absorbing excess nitrates.
You want to get the detritus (fish waste) and uneaten food out of the gravel before the beneficial bacteria turns it into nitrates. Failure to vacuum gravel leaves a breeding ground for nitrates at the bottom of your tank which is a nitrate factory ... especially when stirred.
The majority of BB resides in the filter and there is zero risk that vacuuming the gravel will remove beneficial bacteria attached to the gravel. Think about it. Water in a typical filter is running over the BB on your bio-media at a high velocity (ie 200+ gph over a small space) and it does not flush away the BB from the bio-media. Likewise, water being siphoned running over the gravel will not remove BB that is attached to the gravel.
Since I started vacuuming my gravel weekly I have never had an algae or a bacterial bloom and my water remains crystal clear and polished and all parameters are in check.
