Unlike the standard filtration system installed on most portable spas, where the filter cartridge is integrated into the skimmer, these filter housings can be placed out of the spa. We recommand this system when building a wooden or concrete hot tub for example, or when repairing, if you want to relocate the filtration of your existing skimmer.
With Top-Load models, you can also remove the filter cartridge from above (hence their name) to change and/or clean it without putting dirt (leaves, hair...) back into the tank.
These filter housings come with a Bypass system, which includes a bypass valve that opens when the water pressure is high, to prevent damage to the filter cartridge. The system makes this filter ideal for spas equipped with a two-speed pump. The water is fully filtered when the pump is running at low speed, but the valve opens to let some of the water pass without filtration when the pump is running at high speed, also preventing pressure from being lost in the massage jets.