A pool/spa skimmer includes a housing, a face plate, and a flexible weir
gate. The housing and plate are dimensioned to allow water to flow in a
vertical column. The interior of the housing has a curved wall so that
when a column of water passes through the open gate and into the housing,
a whirlpool effect is realized. A vertical filter cartridge is mounted on
a rotational bearing so that it can spin about its axis. The inlet of a
pump is coupled to the cartridge via the bearing and is also coupled to a
second water inlet via a vacuum operated valve. The outlet of the pump is
also coupled to a water jet which is arranged to enhance the whirlpool
effect.