Please define "a lot of water". When filtering in GC, you can sometimes expect to be purifying 20-40 gallons of water, likely 3-4 times during the trip. So it is important to have a system capable of such volumes. Brady's electric RO filter-in-an-ammo-box worked great. I have also used chlorine crystals with a flavor 'neutralizer' with good results, but that requires very clear water.
There are usually enough clear sources off of the main stem in GC that don't require settling, but maybe not so much with other Colo Plateau Rivers.