 Correct use of the return jets is the most effective way of removing disinfection by-products caused by deeper decomposing organic waste and drawing it into the consecutive dilution system for immediate disposal.Other equipment which may be optioned in the recirculation system include pool water heaters.They can be heat pumps, natural gas or propane gas heaters, electric heaters, wood burning heaters, or Solar hot water panel heaters – increasingly used in the sustainable design of pools.