A swimming pool water circulation system includes up to two sets of at
least two active main drains connected to a "Y" or a "double Y" connector
and then, via a single line, to a single canister filter. Jet nozzles
arranged in at least one bank on the pool walls use return water to sweep
sediment down the pool walls and to cause a vortical flow of the water
above the drains. The additional main drains can be deployed closer to
the pool walls where they can better intercept sediment from the jet
nozzles. Up to two pumps can service each canister filter. Additional
suction may be obtained by diverting a portion of the water from the
pressure side of the filter through a venturi in the canister filet
housing. Additional components and valves managed by a controller can
facilitate sequential cleaning of the pool by zones during normal
operation without unduly affecting normal filtration of pool water and
can provide for additional cleaning via robotic devices.