55 gallon salt filter

[flame_fish]

So my father has a 55 gallon tank with a saltwater filter pump thing I guess? It hasn't been used in years & i was just wondering could I still use the bacteria in that filter for my FRESHWATER fish tank? Or it could only work with a freshwater filter? Thank you!

 

[BlaseMrNiceguy]

If it hasn't been used in years more than likely it has no bacteria, it would be a different kind even if it had the bacteria so it wouldn't do much for the cycling process. My guess is its some sort of sump that being the case you can use it on a freshwater setup no problem it would just be used as a refugium.