That actually made me laugh.
I understand that your not familiar with forums. It also appears that you are typing from a phone. One thing I think would help
Yes this tank is the 75g. It is situated about a foot from the wall, under which is the concrete block wall. The joists run perpendicular to the concrete
Oh like this: http://www.youtube.com/watch?v=YAuCa6cVBKw
Way too much flow, go with the AC50 only and make sure to put a prefilter on the intake tube.