I'm using a tom canister filter that has a hob bracket. One small air stone and I'm assuming that they both are responsible. I may diy a sliding glass top as I've seen on here. Would help on evaporation too. Just set up the 29g today, dirted with the old gravel from my 10 as a cap and topped it all with black diamond blasting sand. I think I still have the option to return this light and maybe upgrade to a larger one as I'm not sure this one will give off enough light for the bigger tank.