I do have a low density of smaller fish, as they get bigger and the water gets warmer it will be more of an issue and I will need to set up a filtration system or flow more through it more frequently. I am flushing 40-50 gallons a night through the system real slowly but the water is turned off most of the time. I peridocally check the nitrate levels with aquarium tests strips and so far it has always tested safe even right up to my weekly water change out. I am also removing any uneaten food and cleaning up the fish poop at least twice a day or more. One thing cool about the tank is that all of the poop and uneaten pellets that sink all settle in a 16" diameter circle in the center. It is real easy to siphon out into a 5 gallon bucket and then water my apple trees with it.
