Most pool filter have no provision at all for bio-filtration. (A MUST in fishkeeping.) They also are not designed to handle the amount of crud in the water that goes hand in hand with fish. In simpler terms they clog quickly compared to a properly designed aquarium filter. There are ways to cut corners on almost all aspects of our hobby but trust me on this one...filtration is NOT one of them.
Some components of pool filters...especially the newer backflushable pleated canister type of filters can make a great ADDITION to a monster tank filtration system but you still have to add plenty of bio-filtration in the form of bio-towers...Sumps...bio barrels...large bio wheels...ect.