over flow tanks

[casey]

I am confused about overflow tanks. What r they used for and do I need one for a 75 gal reef tank?

 

[wamp]

Overflows are just a place in the tank where the water flows over and into a sump.
You do not have to have them but they are a BIG plus. They make it easy to add sumps or refugiums under the tank. They also make the tank look nicer not having a big external overflow hanging off the back of the tank.

 

[casey]

I am new to the reef tanks, when u say sump do you mean a filter and a bio wheel. If u know of any good arfticles I could read about please send them I am confused.