With each of our last two trips we have experienced an issue with our gray water tank getting full and not draining normally. The first time was when we had to scoot out of town to get out of the way of hurricane Irma. Over the days of our trip I had closed the gray water valve during transit, then when we got to each of the destinations I would open it every other day, much to my dismay, by the time we reached West Virginia I discovered the tank was full and leaking. The bad part is that the fittings right at the tank were starting to pull loose and draining all over the place! Thankfully it wasn’t the black tank!
I thought the problem was the gate valve because I was having trouble moving it via the cable connected to it. Long and short of things is that I had to rearrange some of the plumbing in order to re-seat the drain fitting back in the tank. I also had noticed that there was what almost looks like Grits on the ground where the tank had drained out. I thought maybe it was something that had been ground up in the disposal in the kitchen sink, like egg shells.
NOW much to my dismay I think I have discovered that since the cable to the gray tank broke a month or so ago, (right at the end of the handle) I installed an external valve until I could get a new cable controlled valve and the time to install it with travel plans ahead of us. Now that we have arrived in Petoskey Michigan, we are experiencing the same issue with the gray tank not draining! Well that is except to leak from the overfilled shower drain etc. and with the gray valve full open, despite the broken control cable!
So I disassembled the gate / drain valve thinking the issue was there again, and having most of the tank draining onto the driveway, I found what looks like about 2 pounds of this grit! I have not done an analysis of the grit or anything, but I think what I am seeing here is the result of having the gray valve open for months at a time, allowing calcium and other deposits to form and collect in the tank. My thinking is that when we hit the road with sloshing and vibration the grit comes loose.
So I discovered with a bit of research that for one, the ground egg shells are collecting in the tank, along with calcium or other deposits, then when its time to drain the tank after a couple of days the sludge if you will goes straight into the drain system and clogs things up! Well I now believe that this video I found below has VERY GOOD ADVICE! Please take time to review it and adjust your long term tank maintenance routine.
I found a great video related to this issue, not naming the grit, but naming the problems!