Heater size ?
 

The main tank is 75G and my sump is 60G what size of heater should I be using if I put it in my sump?

We just had a thread last week on heater sizes, try a search for it in the reef forum. My 75 had a 200w, worked well.

You could just use the manufacturers suggestions as well... Always worked for me.

I'd put a 200 in your tank and a 200 in your sump.
redundancy in heaters is a good thing.