An automatic tank cleaning system includes a water recycling unit having a weir therein and a conically-shaped bottom, a cutting box having a portable weir therein, a hydrocyclonic separator, and a mud tank. Tank slop is pumped from the mud tank to the water recycling unit where solids collect at the bottom. The solids are removed and collected in the cutting box. Water in the recycling unit may be pumped through the hydrocyclonic separator. Solids removed by the separator are collected in the cutting box and the water is directed into a clean water compartment defined by the weir within the recycling unit. Water in the cutting box is collected by the portable weir therein and pumped to the clean water compartment. Water from the clean water compartment is pumped to one or more rotary jet heads within the mud tank. Overflow from the water recycling unit may be directed to the cutting box. A chemical inductor may be used to add cleaning chemicals to the water prior to being directed through the wash nozzle. Turbulence preventers may be included at the inlet of each flow line to prevent turbulence from occurring in the tank to which the fluid is directed.