I just bought a complete tank, let the water sit in there for 2 weeks with the filter on and stuff, I added the water conditioner in the beginning and thats it. Pet store tests water for free. I just took it there like 4 times. Also start using the cycle( a good bacteria water additive) a few days before putting fish in. Have your water tested on the day you want to put fish in and if its good get about 4 fish. You don't want to get too many at first because it will overwhelm the aqarium and the bacteria in the water won't be able to keep up with the breaking down of waste and unconsumed food.