Freshwater filter

[Amstar]

I have a 30 long tank that I would like to use for filtration on a 125 gallon freshwater tank.

I am use to making saltwater sumps with live sand, rock an macro-algae .... Just never made one for a freshwater tank.

Got any ideas

[Viggen]

I think it depends on what you want in the tank

Easy way is under gravel filtration..... Not sure how popular that method is ..... Requires more maintenance. Vs other methods due to having a thicker substrate in the tank which need cleaned

You could do a few hang on the back filters.... I always thought of those the penguin bio wheels worked by far the best

Another option is canister filters..... They can work well however are a bit more difficult to service/maintain

If you want to use your 30g sump a wet dry filter is a great way to go.  It's the bests of the above methods and is easy to maintain.