hagens or maxi jets, i prefer the hagen aquaclears to any, but are bulkier and higher priced thant the maxi jets, but worth it
in a 75, i would have at least 4(they can be hid behind the rock
one thing i would say is powersweeps are not as good as they would have you tink, adn i will not have a rio, when they do die,they have been known to spewing grease into the tank, not all, but in their case, it is often enough that i would prefer not to chance it
HTH