Just bought the filter max 3 for my aquaclear 70 or 110. Have super naturals black sand and im just wondering how good this thing is at catching sand. Really don't want it to hurt my impeller. Also i cant decide between the 70 or 110 for my 29 gallon. I want to get a banded gourami, tetras, and corys. Is the 110's flow too strong, is it worth the extra cash, or is the 70 good enough? THANKS.