Method first applied in 1956 on eutrophic Lake Kortowskie using wooden siphon pipe. Pipe drained nutrient-rich hypolimnion water to Kortówka River at 180 liters per second. Initial results modest due to inflow water quality and pipe depth. After years, water clarity improved, oxygen deficit shortened, algal blooms reduced. In 1974-75, fiberglass pipe installed reaching 17.2m depth with 250 liters per second capacity. New pipe operates flawlessly today without energy input. Method adopted on lakes Hecht, Piburger, Reither, and others globally. In Poland, applied to Lake Rudnicki Wielkie with three pipes totaling 90 liters per second. Low cost due to passive siphoning. Drawback: polluted water enters outflow river. Unsuitable for lakes without outflow. Strong flow can lower thermocline and worsen oxygen deficit. Hydrobiologists recommend for simplicity and savings where feasible. Device named Olszewski pipe.