Herbie overflow

[jcrow802]

I am getting back into the saltwater/reef tanks again. I haven't done this in about 10 years. I picked up a 75 gallon marineland tank with corner overflow last week. I want to run a herbie overflow. There is a 1.5 inch pvc pipe for drain to pump and a 1 inch for a return. Should I keep the pipes the same diameter? Make the 1.5 the emergency pipe or the main drain

 

[cromag27]

1" main, 1.5" emergency.