Need help in picking a flow for return pump

[gabrielrodon]

Hello i'm new in the salt water tanks and i currently have a 55g tank that has been set up for the last 4 months i'm using a canister filter at the moment. But i'm upgrading to a 75g and i'm going to do a overflow but not sure what size sump/refugium and what gph should i get for the overflow and return pump?

 

[JOKER]

Go as big as possible on sump. Return pump from 5-10 times tank volume per hour should be sufficient..