Johnny G1 wrote:
Leave both closed and open black only to dump and then back flush black tank with a bit of grey water, do this 2-3 times and the black tank will be a lot cleaner, Trust me we have tried it all and my method works the best for me, you can leave a lot of stuff in the black tank other wise that you won't get out. Just my thought's.
I do that with a Flush King, but slightly differently. My grey tends to fill much faster when we have FHUs, so I almost always have a black tank at 1/3 when my grey is full. I just transfer some grey into the black and re-close both valves instead of dumping the entire grey. That usually nets me an extra day of grey use. Plus more water sitting in the black is better. I've had to deal with the dreaded pyramid. I will not let that happen again.
40G black and 60G grey and they can fill the grey in a day. I swear that tankless water heater encourages DD and DW to take far longer showers than they really need.
