gallons per sq ft

we have an old post war house downtown kelowna, only about 900sq/ft, with a display in the livingroom totaling over 1500 gallons, plus some other smaller stuff.... then the garage will house the 7500+ shark tank, and a few thousand gallons of other holding tanks, garage will only be about 450 or so sq feet, lots of gallons per sq feet and it looks like even more cuz the place is soo small...