Black Tank flush with valve closed

I hook the water hose to the tank flush and run it till the black water tank is full, then I pull the lever and dump. I leave the tank flush running for around 20 minutes. Then close the valve and let it run another couple of minutes. Shut it down, and I'm good to go another week.

In our 7th year of fulltiming and doing it that way from the beginning.

If you think you can't remember you are running the tank flush, then by all means don't do it that way. :)

maillemaker wrote:
I never add water back to an empty black tank.

...

It's clean enough - when it's empty and I look down the hole I can see daylight through the milky walls of the tank.

Not disagreeing with you, but couple things caught my attention.

If you're camping frequently, I can see where it wouldn't matter if you store with water in the tank.

Second, I've never seen waste tanks that weren't black. So that was a new one on me.

winniman wrote:
Yes, but it is also common for said people to get distracted. This results in a very messy flood in your rv.

which is why I add 5-gallons of water via the toilet instead of the flush-out.

Yes, I close the drain valve with the flush running to add a bit of water back into the tank.

I've also become distracted and then the tank split all the way across the bottom. I'm not sure if it's related to pressure from the flusher, or just overall water weight that caused the split. I still close it to add water for next use. But I always stay focused now.

I'm always surprised how much the flush system removes. I've drained. Added a good 20 gallons and drained again.

Then hooked up the hose and with a clear waste connector you can see it working.

I never add water back to an empty black tank.

But when I go to dump my black tank, I always make sure it is full before dumping. If it is not full, then I have a small block of wood I keep in the bathroom that will wedge between the wall and the flapper valve, keeping the flush valve open and the flapper open, so that the toilet will fill the black tank.

Obviously you have to pay strict attention here and not wander off or you will flood your RV with poo water. I have never had that problem.

Once the tank is completely full, I pull the waste gate and let 'er rip.

I figure the full tank gives a nice "power flush".

I never use a hose or any other sprayer things to hose down my tank. It's clean enough - when it's empty and I look down the hole I can see daylight through the milky walls of the tank.

wopachop wrote:
Is it common for people to close the valve with the hose still running in order to prime the tank with some fresh water?

I do close the valve with the flush water running, even though there are warning signs about never ever doing that. I'm just careful to not wander away or get distracted. I have to exercise the same caution when I'm filling my FW tank, because it can burst too. I like to get a half tank or so of water in the black tank to help float solids out. I might even do that a couple of times. I am definitely not obsessed with super clean tanks.

But your question seems to be if anyone does that to prime their black tank after dumping is complete. I don't do that. I go run a couple of bowls in the toilet, adding my chems at the same time. I don't think the flush system would give me a good estimate of how much water I was priming in the tank. Too little and I risk solids drying out, too much and I'm just wasting capacity for my next outing. Using the toilet bowl lets me see how much I'm adding.

winniman wrote:
Yes, but it is also common for said people to get distracted. This results in a very messy flood in your rv.

I got distracted like this once with different results: (1) The result wasn't messy because the tank had been flushed well first, and (2) It wasn't a flood because the overflow ran out the roof vent. It taught me to not let myself get distracted during this operation.

(Some rigs have a sink or shower plumbed into the black tank, and they would have had a flood).

winniman wrote:
Yes, but it is also common for said people to get distracted. This results in a very messy flood in your rv.

Yes, and I also do it to help flush out solids, set a timer on my smart phone for no more than 5 minutes.

Yes, but it is also common for said people to get distracted. This results in a very messy flood in your rv.