Black Water Tank Buildup AND Removal

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Black Water Tank Buildup AND Removal

May 06, 2016, 08:09:39 pm

I am in the process of replacing the drain valves on the gray/black water tanks and sharpening up the wet bay a bit while doing so.

After replacing both the valves I opened the one at the black water tank and looked up inside with a flashlight, and from the looks of things there may be what some refer to as a 'mound' on the floor of the tank. I can see the edge of a light brown substance extending 1-1/2" - 2" above the tank bottom, which may actually be covering the bottom. I poked at it and was able to poke through it with not too much effort, so I filled the black water tank half full of water and then drained it, hoping to send that blanket of crap with it. But that didn't happen, so now I'm going to get some Rid-X and Dawn to pour in along with 1/2 tank of water and let it percolate for a week before draining.

I don't know what the PO's habits were for maintaining the waste tanks, nor do I know what the heck I've got going on here but
what if the 'blanket' floats?............................ Ice cubes and a road trip?

Re: Black Water Tank Buildup AND Removal

Reply #1 – May 06, 2016, 08:16:31 pm

As you have the valves off and can see the """"" why not have someone with thin arms etc put there hand in there and remove it"" nylon gloves will be good enough for protection. Just pretend you have a Baby and have to clean the mess up?? We all did it without thinking- correct.
JohnH

Re: Black Water Tank Buildup AND Removal

Reply #2 – May 06, 2016, 08:22:38 pm

It's too far up inside and across the tank to reach by hand.

Just to clarify.........there's no blockage.
I just don't like the idea of 2" of a gelatin-like substance in the tank, that's growing.

Re: Black Water Tank Buildup AND Removal

Reply #3 – May 06, 2016, 08:27:55 pm

Quote from: Traveling Man – May 06, 2016, 08:09:39 pm

from the looks of things there may be what some refer to as a 'mound' on the floor of the tank.

I don't know what the PO's habits were for maintaining the waste tanks, nor do I know what the heck I've got going on here but
what if the 'blanket' floats?............................ Ice cubes and a road trip?

Most likely someone who left the black valve open when camped. Grey one OK, black no or you get that mound.

Dawn and water should work well, especially if you drive around and agitate things. Over time and proper use it should dissolve and "go with the flow" out the sewer hose just fine.

Re: Black Water Tank Buildup AND Removal

Reply #4 – May 06, 2016, 08:36:21 pm

Hose down into toilet? Cut the end of the hose off to prevent hooking on things when pulling back up. Sounds like the dreaded mountain caused by leaving the black tank valve open all the time.

Re: Black Water Tank Buildup AND Removal

Reply #5 – May 06, 2016, 09:10:22 pm

Quote from: Barry & Cindy – May 06, 2016, 08:36:21 pm

Hose down into toilet? Cut the end of the hose off to prevent hooking on things when pulling back up. Sounds like the dreaded mountain caused by leaving the black tank valve open all the time.

The toilet has an bowl overflow valve I think on ours.

Versus jam the electric flapper open?

So overfill the bowl?

Or hook up our third valve and clean section as it has a hose bib on it and back fill the tank?

Re: Black Water Tank Buildup AND Removal

Reply #6 – May 06, 2016, 09:11:37 pm

Epsom salts 16 oz.... 25#of ice..... down the toliet, let sit 20 min..
dump in 2 .. 5gal buckets of water..... Take a 20 minute drive.. with bumps and stops.... another 10gal.... dump..

My dad and I got this from the gypsy journal guy... when I bought the 88, had the same problem....

Re: Black Water Tank Buildup AND Removal

Reply #7 – May 06, 2016, 11:54:32 pm

TMAN - Next time you are going for a ride - put 10 or 20 lbs of fresh ice and about 1/8 flu black l tank take a drive with a lot of starts and stops. Try that

there are also flush devices for the black tanks that are pretty effective.

Re: Black Water Tank Buildup AND Removal

Reply #8 – May 07, 2016, 09:58:35 am

Quote from: Tim Fiedler – May 06, 2016, 11:54:32 pm

there are also flush devices for the black tanks that are pretty effective.

Tim makes a great point, and I know the U320's from 2003 have a built-in tank flush - attachment point for the garden hose is in the utility bay. You just want to be connected to a sewer hookup or dump station with the black tank valve open while you use it. Not sure if they also installed it in the U295's, though. Off to check the Wiki....

Re: Black Water Tank Buildup AND Removal

Reply #9 – May 07, 2016, 10:25:59 am

I have the tank flush and use it to fill the tank with fresh water when trying to dislodge the mound.

Also, I have access to a hot water heater within 15' of the coach, so what about putting hot water down the toilet with some Dawn?

Re: Black Water Tank Buildup AND Removal

Reply #10 – May 07, 2016, 11:03:15 am

Those flush wands that you put on a garden hose work very well. I like the ones that have a rotary tip. They will also keep your level sensors clean when used on a regular basis. Have a great day ---- Fritz

Re: Black Water Tank Buildup AND Removal

Reply #11 – May 07, 2016, 12:12:05 pm

Quote from: Traveling Man – May 07, 2016, 10:25:59 am

...so what about putting hot water down the toilet with some Dawn?

Hot water is always good for any cleaning job. There used to be a popular holding tank formula around here: 1/2 cup Dawn + 1/2 cup Calgon dissolved in a gallon of water...flush it down the toilet before a day on the road so it will get agitated thoroughly. I use it occasionally - if nothing else it smells good!

Re: Black Water Tank Buildup AND Removal

Reply #12 – May 07, 2016, 12:29:47 pm

Quote from: Chuck & Jeannie – May 07, 2016, 12:12:05 pm

Hot water is always good for any cleaning job. There used to be a popular holding tank formula around here: 1/2 cup Dawn + 1/2 cup Calgon dissolved in a gallon of water...flush it down the toilet before a day on the road so it will get agitated thoroughly. I use it occasionally - if nothing else it smells good!

I would add ice to that cocktail. Shaken not stirred and find a bumpy road.

By the way, my 2003 U295 has the black tank flush built in. I carry a short and black water hose for this.

Re: Black Water Tank Buildup AND Removal

Reply #13 – May 07, 2016, 12:47:48 pm

Watched a video awhile back. The guy tested the ice theory and his conclusion was that it was a waste of time and energy. The ice could never get moving enough to clean anything.

Re: Black Water Tank Buildup AND Removal

Reply #14 – May 07, 2016, 12:56:27 pm

I saw the same or similar video. With a clear tank and simulated buildup. The ice did very little to solv the problem.

Re: Black Water Tank Buildup AND Removal

Reply #15 – May 07, 2016, 02:09:27 pm

Been using the calgon trick for 15 years and have always had good luck.

Re: Black Water Tank Buildup AND Removal

Reply #16 – May 07, 2016, 02:17:01 pm

The ice might work in an otherwise empty tank. Otherwise i suspect it would simply float on top and do no good on the bottom.

Re: Black Water Tank Buildup AND Removal

Reply #17 – May 07, 2016, 04:59:24 pm

Tom, my thoughts exactly. Unless you put just enough water in to let it slosh around some at the bottom of tank

Re: Black Water Tank Buildup AND Removal

Reply #18 – May 07, 2016, 05:43:18 pm

T-Man, calgon plus dawn sounds best.

But since I often take the more difficult road, I can just see me with an electric drill and some attachment to stir things up, just as you tried with a stick through the open waste valve.

I would likely select or make up the wrong attachment.....hmm, a brush or a metal propeller?.....and tear a hole in the tank.

Naw, I am encouraged to just use the calgon plus dawn as a preventative by doing that periodically.

If nothing else, I would watch again that Robin Williams movie, RV.

Re: Black Water Tank Buildup AND Removal

Reply #19 – May 08, 2016, 08:17:30 am

Curious if the Ridex works for you. We have used bio enzymes both black and gray. The first time we filled the tank and placed baking soda in it for a one day run. Emptied it and brought back to a quarter full. Put in the enzymes and let them enjoy. After that, when tanks are emptied we make sure the bottom is covered and apply. It has worked for us as no smell from either tank.

Re: Black Water Tank Buildup AND Removal

Reply #20 – May 19, 2016, 05:24:46 pm

UPDATE;

2 weeks ago I bought a box of Ridex and a big bottle of Dawn. Along with them I put about 30 - 35 gallons of water in the tank, both down the toilet from a 5 gallon bucket to agitate as well as through the flush fitting in the wet bay.

Today I went out and dumped another 5 gallon pail down the toilet and lifted the coach as far as possible on the passenger side. Then I opened the drain valve and heard, as well as felt the flow......................but then it stopped. I picked up the sewer hose and gave it a good thrashing while lifting it and felt things start to move again.

When the tank was empty I repeated the water procedure. Again I could feel things moving so I jostled the hose some more and everything seemed fine. I waited till it completely quit draining and leveled up the coach. Then I took a flashlight and looked inside the drain to find that the black water tank is completely cleaned out.

Great news, and thank you all for your input.

Re: Black Water Tank Buildup AND Removal

Reply #21 – May 19, 2016, 10:04:23 pm

T-Man. Anybody who will look up the drain to check out the black tank gets a like from me. The Dawn/Calgon/warm water magic mix after every empty has worked very well for us as a preventative measure. We rarely dump at less than 60% full and have a third valve to help keep things clean.

Good job!

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