Very tight budget!

[Nemodao]

I'm getting a 45 gallon tank with a hang on the back protein skimmer. Shout I get a canister filter or hang on the back?

 

[BigRedsReefs10]

Hob or just the skimmer, canisters are better for fw. JMO

 

[TheTodd]

If you have a good HOB skimmer, you might not even need a filter. Live rock/sand covers your bio filtration and the skimmer should grab the rest. If you add a filter, you will need to clean it all the time or it will collect gunk and become a nitrate factory.