I had somequestions about the skimmer. I am looking to upgrade and have always like the hang on type and wondered if this model could be used in a sump if/when I upgrade?? If I use this on my current tank (55), would I need to modify anything of the tank. had read that someone had to drop the level of a tank 2" for it to work?? Didnt make sense but thought I should check. Lastly, is the a skimmer box that can be used with it as a hangon version?