Cloudy water
white cloud or green cloud?
best to bring a sample of the tank water down to the store
a good 8 ounces is best
maybe in a seperate bag bring a sample of your tap water, too
we will test it
probably give you another bag o' Uncle Ned's good dirty water
probably we'll suggest a substantial water change
(we'll show you how to do that)
possibly show you how to clean but NOT OVERclean the filter pads
possibly sell you a bottle of ProClear
possibly sell you some live plants
ask you a bunch of questions
like
How many hours a day is light on?
How many/what kind of fish?
How much and what kinds of food?