I just moved into a new house and want to fill my 90 Gallon aquarium. The subfloor conists of measured 4x5 joists spaced 48" apart with tongue and grove planks that are 2x4. On top of the tongue and groove is 3/4" plywood and on top of the plywood is 3/4" tongue and groove african walnut. The tank position is next to a wall. When going into the crawl space I found that the wall is sitting right between each of the joists (it is not sitting on the joist). Additionally, the dirt in the crawl space is extremely compacted and would be extremely difficult to dig through. Can this hold the aquarium or do I need to reinforce the floor. The aquarium is calculated at around 1000 lbs. The aquarium is 4ft by 1.5 ft. This gives me 1000/6= 166 pounds per square feet. Also, I need to drill a 2" hole in one plank and a 1 1/2" hole in the other in order to plumb the aquarium into the garage. The best way for me to do this is to cut a hole in the wall and drill down through the wall base plate and through the subfloor.