Overflow box

[Jim Corey]

Could someone explain the overflow box for me ( what it does, should you have one, ect.)? Sorry for the dumb question.

[anthworks]

The overflow takes water from the main tank and moves it to a sump or skimmer. It's like a drain on the tank.

[Jim Corey]

I have not bought the HOB skimmer yet. Would I need an overflow box or is that only if you have a sump?

[der_wille_zur_macht]

Only if you have a sump.