Drilling A Tank

[Jewel]

Can you guys tell me what size holes to drill? I was thinking 3 inch and a half holes for the external over flow and 4 one inch holes for the returns. The returns would be in the four corners on the back using a check valve so they don't drain back to the sump. The 3 holes in the over flow would consist of 2 to the sump and one to the fuge.

Is there a formula to use for the return pump so as to not over flow the tank?

 

[Pistol]

The holes have to match what ever bulkheads you go with, sch 80 bulkheads require larger holes than sch 40

 

[Sewerat]

Jim. Do a search on bean animal drain. If you're drilling you want to make it silent one is full drain, one is trickle drain and one will be dry unless one of the other two gets blocked somehow. And returns not sure why you think you need 4 2 would be more then enough. The fuge dosent need much flow going to it so you could either T from the main drain or out the trickle into it, the emerge could go direct into the pump spot, it should in reality NEVER get used. That is it's purpose.