Disclosed is an improved water treatment cavitation reactor cone. The tank operates on a continuous flow of fluids which are subjected to ultrasonic waves in combination with a high level of injected ozone. The treatment tank includes a tangential inlet that induces a rotating flow into the tank thereby increasing the mixing of the ozone within the effluent. The effluent is further treated with DC current. The treatment tank provides a cost efficient and environmentally friendly process and apparatus for cleaning and recycling fluids as contaminated as frac water, used to stimulate gas production from shale formations, as well as other types of fluids having various levels of contaminants such as aerobic and anaerobic bacteria and suspended solids. The calcium carbonate scaling tendency is reduced to an acceptable level without the use of acids, ion exchange materials, or anti scaling chemicals which is of economical and environmental significance and benefit.