RO units/water filtration units...What can you do with them?

[Hustler]

I have a 3 stage carbon/clhorine/clhorimine system plumbed into my tank that I have no idea what to do with now..... It was used for a constant drip water changer on my freshwater system....
Also an ro unit that either needs to be rebuilt or turned into something as well as my 2 stage carbon/micron i used to use for alge again in fresh.....
Is there a way to set them up with a pump for carbon/gfo?
Can i install a new ro membrane.....is it worth it for water changes/top up?
I hate to dump stuff if i can make it work under the thak attached to the sump with a pump or used plummed into the tank with a flow ect ect....
Any ideas attachments/canister mods to make this stuff usefull with a salt setup would be MUCH appreciated