Thanks for you comment on my little glass water gardens with snails. Yes my water eventually became high maintenance as my snails became abundant and I fed them generously. I had to do a lot of partial water changes and decided to buy http://www.amazon.com/United-Pet-Gro.../dp/B001D71580 and got rid of the filter part and hooked up the wee little air filter to a split air tube with air stones and left the lids open a little to not crush the air tube. I was pleasantly surprised to find out that the air bubble keep the water super clear and I have not done a partial water change in two weeks, and feed generously still. I've only had it for about 2 weeks and I'm curious myself to see how long before I need to do a partial water change.