I'm thinking about getting a 10 ish gallon tank and drilling it to allow for a sump without going over the rim. My question is..... What size bulkheads/holes and piping or hoses should I use for the drain and the return. I'm inclined to think the drain should be larger but I don't know for sure. If anybody has any suggestions I'd love to hear them. Thanks in advance!
Yes, the drain should be larger (could be the same size if there are multiple drains). I know there's a chart floating around with recommended hole diameter sizes relative to flow. If I find it, I'll post it.
You are going to use the same size bulkheads in most cases.
Just more if more flow is needed..That being said my 120 and 180g only had 2 out and 2 in so you should be fine.
As for pump you need to figure in head pressure/loss and then how much flow.
I ALWAYS oversize the pump and use a valve after the pump to control flow if needed.