JT & Mike,
I have a 20 gallon tank with both the under gravel and an outside filter on it. The outside filter will clear the water after a cleaning quicker than the under gravel one will and it has 4 tubes with air stones in it. I never had the experience Mike did when I got mine new. I washed the gravel and everything and it was a little cloudy from the minerals we have here for about 30 minutes and then turned clear. My biggest problem is the green algae that covers the inside walls of the tank. I have to brush that off every month or so and for a few minutes I can't even see the back side of the tank and then it will be all clear. I did take a sample of my water to the pet store to have it tested and they told me it was the minerals that caused the cloudiness for a short time.
Ron
