Overflow shaft type of pools are found mostly in public areas. Their characteristic feature in addition to the design allowing the outflow of water through the shaft (channel around the pool or for example, on two sides) is to have a storage tank for water. Such a tank provides a continuous supply of water for pumping, and fresh water is added to the tank to supplement the losses. The cost of pools with a shaft exceeds the cost of skimmer pools due to the construction complexity and additional technology (storage tank).
