A system for altering water properties in an outdoor body of water includes a holding vessel configured to hold water. The holding vessel has at least one wall extending above a mean surface water level. The system also includes at least one conduit extending downward from the holding vessel. The at least one conduit has a length extending to a depth at which at least one property of water at the depth differs substantially from that of water at the surface. The system further includes at least one aperture formed in at least one of the holding vessel or the at least one conduit and located at a distance below the mean surface water level. Further still, the system includes at least one one way valve coupled to the at least one aperture and allowing flow of water in only one direction.