I am concerned about the minimal nitrite level after 1 year. Nitrites and ammonia should be at zero (I assume you didn't mean nitr*a*te). Is this a plastic/resin "made for aquarium use" log, or is it a real log? Is it open at both ends or just one? If it is open at both ends there should be enough waterflow without any other intervention. If it is closed at one end, yes, an airstone will create flow - IF that is what is causing the problem. If it is a real log, it should have been cleaned very well before adding to the system. Check this website - www.wetwebmedia.com. They have an ask the expert forum - they do require that you provide system details (water quality values, size, # of fish). I'm more concerned about the nitrites though, because nitrites are deadly to fish.