How do you calculate how large of a return pump you need?

[agoutihead]

Whats the formula to try and figure out how large of a return pump you need?

 

[stuccodude]

when i purchased mine i emailed marine depot and told them what i have and being i had the overflow and sump design it was important to have the perfect flow and they were very helpful, good luck

 

[Slakker]

This is a good start:
http://reefcentral.com/calc/hlc2.php