I also use a SL-65...and have about 30-40 sponges / box filters running off of it (I don't use airstones). It's not the quietest air pump in the world, but it's pretty good for the price. Jehmco has some great ones that are nearly perfectly quiet.
I'd recommend one sponge and one box filter (both air driven) for each tank/compartment. Sponge for bio and some mech and box for mechanical and chemical (carbon) if needed/desired.