How much flow for sump and in tank?

[Aquattro]

I'm setting up a 50g right now, I'm going to use a MAG7 for return, so probably about 400gph after losses. I like longer dwell time in the sump.

In tank depends a lot on what you're keeping. SPS in a bare bottom tank can take 100x turn over, softies and such with sugar sand, not so much. As stuff grows, you'll find you may have to increase flow.

Start with the in tank korallias, see how they work. If you're doing a dingle return, start with the 600gph. Multiple outlets, go bigger.