Over time, all kinds of stuff collects on the inside walls of the black-water tank. This creates sanitation problems and gives false readings at the monitor. An easy-to-make, affordable pressure-wash “magic wand” can cure this.
Using ¾-inch PVC pipe, cut a piece long enough to go from at least 7 inches above the toilet to the bottom of the black tank. On the top end, glue a 90-degree elbow, a short nipple, a shut-off valve and a female garden-hose adapter.
At the bottom end of the wand, glue a PVC cap. Since the tank has four sides, drill four 3⁄16-inch holes at the 12-, 3-, 6- and 9 o’clock positions, about one or two inches from the bottom of the pipe.
Next, drill a hole in the middle of the cap. You might have to come up with your own size of the holes, depending on your water pressure. I recommend cutting the pipe longer than you might consider necessary, so you can cut, recap and redrill if necessary to achieve a more desirable water pressure.
Make sure the tank is empty and hook a garden hose to the wand. With the RV water pump off, open the toilet-flush flap and carefully insert the wand until it reaches the bottom of the tank. Open the PVC valve and move the wand up and down in a rotating motion for several minutes and then empty the tank.
Do this several times and you will be surprised at how much unwanted material will be removed, leaving a fresh tank and more accurate monitor readings.
Eddie Knight, Green Cove Springs, Fla.