Ok so I was planing on buying a 40 cube but ended up with a 75 rr tank. I have a 20 long that I was going to use as my sump on the 40 cube. Can I use the 20 long for a sump on the 75? My stand is 18 wide but I barely fit the 20 long inside so I am not sure I can even use a bigger sump. Thanks in advance for the suggestions.