People always assume it's a bad idea to do a 70 or 80 percent water change. I already have the python in the tank draining water, might as well change a large amount. And I'm very accurate with the temp when filling it back up, can usually get it within .5 degrees. And it's just like a sitting water smell, right now I'm two feet away from the tank, and I actually can't smell it, but when I'm over the tank with the lid open, it smells stale, a little fish like. Its probably normal, I'm just curious if anyone else notices this, and anything that will eliminate this smell