I don’t think you will die using it!
There are several ways to use it and I usually hook it up and turn it on while dumping the black tank. Once the tank is pretty much done I close the black tank valve and allow it to flush with the hose. I give it about 5 minutes and open the valve. I may do those several times until the water comes out reasonably clear. I the shut the water off and open the gray tank. Allow the gray tank to flush the line. Once the water stops coming from the hose I close the black leave the gray open and am finished.
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