Having finally managed to arrange for someone to come and drill my new tank for sump installation I had a sudden thought, just how big a hole should it be?
The display tank is about 85 gallons and the sump is made of two 15 gallon tanks (pre drilled to link).
I would have a hole to fit 1 1/2" pipe so a 52/53mm hole. Just check the tank connector will fit. you may want to put more flow through the tank now or in the future so this will enable you to put up to 7000lph through with no problems. It won't cost you any more (apart from the larger pipe work) too big is better than too small.
