Black Tank Flush

[BB_TX]

Originally Posted by Chief Brown

.........Am I wasting water because my black tank sensors still do not work? The sensor shows full all the time.

My tank sensors never worked right. I used pretty much the same procedure as you but using a clear extension at the dump pipe. After each closing and opening of the drain valve I would see additional solids come out, each time getting less and less until it is mostly just brown colored water coming out. So no, you are not wasting water. Each cycle gets a little more of the solids out so less to settle and solidify on the bottom of the tank.

[Cat320]

Originally Posted by BB_TX

.... using a clear extension at the dump pipe...

Agree. I have a 90 degree clear fitting on the discharge end of the coach. There is no guessing and/or wasting water trying to determine when the tanks are "clean."

[Daryles]

I also have the Valterra gate valve. I put a 3" clamp around the connector end to prevent it accidentally falling off going down the road.

Hblick48,
It would depend on how your tanks are configured in your rig if this trick of sharing tank space would work.
I have a 3130re. The galley tank is mounted higher in elevation than the bathroom grey or black tanks. Therefore my galley tank will always drain into my grey or black tanks (I do the grey tank backflush trick too).
However, the 3" drain pipe between the tanks to the gate valve will hold about 8 gallons giving you some extra boondocking space for grey water. I wouldn't do it with the black tank.

[Hblick48]

Originally Posted by Daryles

I also have the Valterra gate valve. I put a 3" clamp around the connector end to prevent it accidentally falling off going down the road.

Hblick48,
It would depend on how your tanks are configured in your rig if this trick of sharing tank space would work.
I have a 3130re. The galley tank is mounted higher in elevation than the bathroom grey or black tanks. Therefore my galley tank will always drain into my grey or black tanks (I do the grey tank backflush trick too).
However, the 3" drain pipe between the tanks to the gate valve will hold about 8 gallons giving you some extra boondocking space for grey water. I wouldn't do it with the black tank.

All 3 of my tanks the same size and are mounted between the main frame rails on the same level.

Regarding using the "burp" method to determine when to dump the black tank, don't do it. It happened to me once (because I thought I had dumped the tank, but didnt). Burping split the seem between the top and sides of the tank. Had to replace it, and had previously replaced the main grey tank (cracked below the discharge fitting). Both are now properly supported so shouldn't have future issues.

[DutchmenSport]

Ah, it's so nice to read that some other folks also back-flush and actually see the value of it. Far to many times (on different forum sites), I get heckled because folks just don't think it benefits anything, that their tanks get cleaned out by simply doing a one time dump with "plenty of water."

!

[glb1950]

Hence the reason I'm on this forum. Pick the brains clean of all useful information from more knowledgable people than myself.......before I destroy everything trying to do it my way.(usually the wrong way) Thank you

[CaptnJohn]

OP has a good method for back flush, there is only ONE way to eliminate the frustration and aggrivation of reading the sensors~~ I realized this decades ago,,, PRETEND THEY DO NOT EXIST!!

[jcurtis934]

The other way around those cheap crappy sensors is to install external sensors on your tanks. The added benefit besides knowing exactly how much stuff is in those tanks, is that it takes time to pull the coroplast and install the sensors...which means less time available to maybe hoist one too many adult beverages, less time to do endless shopping for stuff you may not need, and it provides entertainment for park neighbors who wonder what the heck you are doing under there!��

[R.S.O'Donnell]

Admittedly not for everyone but our solution was to switch toilets altogether.

It'll be four years in March with ours. No black tank maintenance/issues whatsoever.

First learned about them from The Wynns:

https://www.youtube.com/watch?v=_E2xOoNov9s

[bcrvman]

Originally Posted by Chief Brown

When I flush my black tank in my 2021 Montana H/C I will dump tank first.
Then I close the valve and flush for 2 minutes, then I dump that. Then I close it off again and flush for 3 minutes and then dump again. I will repeat again for 4 minutes. Am I wasting water because my black tank sensors still do not work? The sensor shows full all the time.

I run the flush for 15 minutes when dumping on a mechanical water timer, then 15 minutes with valve closed to partially fill tanks, pull valve and put another 15 minutes on the flusher. Repeat as many times as needed to get as clean as you want. Naturally I have a 45 degree clear elbow attached to the second shut off valve to judge when clean enough. Why 2nd, so if that one fails, I can reach behind it and shut the next valve in line. With black water I want 3 valves between the crap and the outside world. I also start a 15 min timer on my watch or phone as backup to the mechanical timer. After black is done I then do a similar dump, fill, dump with the grey followed by the galley.

[Camp CA]

You are doing what most folks do. I never rely on my black tank level monitor since always show 3/4 full.

Might add .........consider filling:1) black tank through the flush connection with 15 gallons of water metered by an in-line flow totalizing meter, e.g., $24 P3 P0550 Water Meter, prior to use AND 2) longer than 3 minutes to ensure sufficient water is added to adequately rinse the tank (turbine helps to confirm how much water you are adding during the rinse cycle).

[Camp CA]

Suggest installing a Valterra 3" valve with a clear section and built-in valve with or without hose flush connection and cap on the discharge line. This avoids removing the cap and draining residual gray or blank tank waste on the ground. since the drainage lines do not allow 100% disposal.

[Mikelff]

Originally Posted by Chief Brown

When I flush my black tank in my 2021 Montana H/C I will dump tank first.
Then I close the valve and flush for 2 minutes, then I dump that. Then I close it off again and flush for 3 minutes and then dump again. I will repeat again for 4 minutes. Am I wasting water because my black tank sensors still do not work? The sensor shows full all the time.

I rarely have to flush my black tank. I use the Unique brand microbial chemical treatment in my black tank, and occasionally in my grey tanks. The manufacturer actually tells you not to flush the tank because you are actually flushing the microbes at the same time. Just use plenty of water when you flush the toilet. Not lots and lots, but an average, good flush. Empty your black tank first, “flush” with your grey tank water, and your done. Add about 3-4 gallons fresh water back to your black tank, add more microbe treatment and you are done. Never had an issue. The microbes will clean your sensors as well. They will also break down a poo pyramid, but it will take a while, several hours, for that, but it works. Only time I do a serious flush out is when I put up my RV for winter storage. It keeps my sensors clear and working, though I don't rely on them as even when they are “working” they are not that reliable. The microbes break down toilet paper big time. I would recommend you give them a try. Available at Amazon, Walmart, several places. Do a google search. Read up on the science. NEVER have to go through all the tank flushing and flushing, and flushing. NOT necessary! Check it out.

[Camp CA]

Originally Posted by Mikelff

I rarely have to flush my black tank. I use the Unique brand microbial chemical treatment in my black tank...........

I will try it!! I have used Unique on my boats, albeit the holding tanks are easily dumped since they are vacuumed out with plenty of suction that evacuates not only the holding tank but toilets and long sanitation hoses. Even then, I fill the holding tank up twice and vacuum out to make sure the system is fully flushed.

[badaxemi]

Originally Posted by Chief Brown

When I flush my black tank in my 2021 Montana H/C I will dump tank first.
Then I close the valve and flush for 2 minutes, then I dump that. Then I close it off again and flush for 3 minutes and then dump again. I will repeat again for 4 minutes. Am I wasting water because my black tank sensors still do not work? The sensor shows full all the time.

I use this item when my tank is showing that there is something still in the black tank when I know there isn't.
https://www.walmart.com/ip/Valterra-...zzle/163927729

[Grampa]

I use a Wan down toilet after the back wash with valve open three or four times, shout water off drain tank inbetween , keep water to trailer off when doing the Wan

[BobStack]

I’ve used the Dawn dish soap trick also and have never had a sensor issue. I also use this tank treatment after each dump.

Unique RV Digest-It Holding Tank Treatment - Powder Toilet Treatment (30 Treatments) - 41G-1 https://www.amazon.com/dp/B0742M6GF2...ing=UTF8&psc=1

[glb1950]

Got my Valterra Flush King 45 Degree Reverse Flush Valve Attachment today. What a mouthful. Didn't have a hose other than our drinking hose and didn't want to use that. So just emptied black tank and back flushed grey tank into it about 4 times and got a lot of extra brown sludge every time until I run out of grey water. Will get a hose and next time, will power blast the black tank a couple of times. So far pretty happy with the results. Thanks for all the information in this string. Gettin me some Calgon bath beads also.

[RMcNeal]

Originally Posted by glb1950

Got my Valterra Flush King 45 Degree Reverse Flush Valve Attachment today. What a mouthful. Didn't have a hose other than our drinking hose and didn't want to use that. So just emptied black tank and back flushed grey tank into it about 4 times and got a lot of extra brown sludge every time until I run out of grey water. Will get a hose and next time, will power blast the black tank a couple of times. So far pretty happy with the results. Thanks for all the information in this string. Gettin me some Calgon bath beads also.

I got our Flush King when we had a TT since it didn't have the black tank flush. I still use it so I can back flush the grey tanks, mostly the galley tank. You'd be surprised what comes out of there, even when you're being careful what you let go down the sink. It really came in handy when I first camped in freezing weather to get the frozen block in the sewer outlet thawed from the outside. I wouldn't be without one now.

[Busybob]

The best way I have found so far in cleaning and restoring your tank sensors is your flexible sewe wand. Stick it down your toilet, of course after flushing your tank out, and let it do its thing. Check your sensors. If cleared fine. If not , try again. It should work. This only a temporary fix.