Ok, so a couple of weeks ago, we take our new to us 5er out for it's maiden voyage to test everything out. Along with a couple of other issues, I found that the black tank sensors were saying the tank was 2/3 full. Can't be, so I flush the tank several times. Each time I notice there's still fluid in the tank even though there's nothing coming out. Can't seem to get it all out and the flush is running clear and we have to go home. This week I park it at the Auto Craft Shop so I can work on it and get it ready to go back out this weekend. I bought some sensor cleaner at Camping World which said to fill the tank and let it slosh around while I'm driving. When I go to pour water in the toilet, I notice a bunch of tiny maggot looking worms attached to the underside of the flush ball thing. Gross. Then while I'm using a five gallon bucket to fill my 50 gallon tank, I can only get eight buckets into the tank before it's already coming up through the toilet. Which tells me there was still 10 gallons in the tank.So yesterday, we pull in and get set up and I empty the tank, and again, after the flow stops, there's still fluid in the tank.What gives? Why won't the tank completely empty? Is it supposed to maintain nasty water all the time?

It should empty completely....every tank I've ever seen the bottom slopes towards the dump valve opening. There may be some residual liquid like a cup or so but nothing like you are describing. Sounds like you might have the "Pyramid of Death". A pile of solids at the bottom.You can try dumping a couple of bags of ice in the tank and then drive around to see if it will break up any solids. If that doesn't work then it's time for a camera to see what might be stopping it up.

the bear II wrote:It should empty completely....every tank I've ever seen the bottom slopes towards the dump valve opening. There may be some residual liquid like a cup or so but nothing like you are describing. Sounds like you might have the "Pyramid of Death". A pile of solids at the bottom.You can try dumping a couple of bags of ice in the tank and then drive around to see if it will break up any solids. If that doesn't work then it's time for a camera to see what might be stopping it up.X2, then maybe a good power flush through the toilet to flush the solids that have been left from the previous owner not dumping properly. JMO

Could be the tank is tilted away from the drain. Jack up opposite side of trailer so that the drain is for sure the lowest point and see if more drains out

Is it safe to put an industrial strength drain cleaner, like liquid plummer or something into the tank? That should dissolve any solids stuck in there, right?

Black Tank Won't Empty | Good Sam Community

2oldman
Explorer II
Sep 09, 2014
fj12ryder wrote:
.. it really does seem to happen more often on this forum than most of the others I frequent. I think part of it is the huge disagreement between posts.
Could be. I think it's just plain old laziness. Plus, some posts are just obviously phony, like a 'student' who wants to live in a trailer in upstate NY in the winter.
bpounds
Nomad
Sep 07, 2014
What hasn't been mentioned, and the OP might find good to know, is that you don't want your black tank to ever be completely dry. Doesn't need to be totally clean either, but that's a different issue. Point is, leaving it dry is the fastest way to have a hard dried layer of mud buildup. No need to sweat getting all the water out when you dump.
Big_Katuna
Explorer II
Sep 06, 2014
If you don't have a built in tank rinser I would add one. This is the first RV I have had one in. I use a 6" clear extension. I was surprised how much stuff keeps coming out.
Greene728
Explorer
Sep 06, 2014
drillagent wrote:
Ok, so I took some advice from here and flushed the tank until nothing else came out. Then I turned on my Iphone video camera and taped it to a yardstick and stuck it down the toilet. Very interesting. There isn't any mound or large piles. There's a lot of residual gunk on the tank walls. The pipe isn't exactly on the bottom, so it has a bit of a lip. Hence why it isn't completely emptying. But the most interesting part is that the pipe isn't at the end of the tank (facing the side of the trailer). It's actually at the side of the tank (facing the back of the trailer). Right by the toilet. So when it does flush, the dreaded mound of death goes down first.

So, here's the plan. I went and got some RV Rid-X at Walmart this morning and I've re-filled the tank to about 2/3 full. I'll let it soak overnight. When I leave in the morning, I'll tip the trailer back and flush it out again. Then I'll fill it back up with some calgon and detergent (Geo Method) and let it soak in storage for about a week. Does that sound like it will work?

I think I'd pull it to the camp this way and let everything slosh around and hopefully break the gunk down even more on the way. Then when arriving I'd flush good at the camp dump station then start your Geo method. I'll say this too. The Geo method is good I'm sure, and obviously works for a lot of people. But once you get everything nice and cleaned out, then just flush really good after every use and use lots of water and you'll probably be just fine. We use our toilet as intended and have the black tank flush. After every trip I flush really good and use lots of water. Then I leave a few gallons of water in the tank and flush a RV tank packet down and we have never had a single odor or issue. And leaving some water in the tank at all times so it doesn't dry out. That's very important!
fj12ryder
Explorer III
Sep 06, 2014
2oldman wrote:
fj12ryder wrote:
But hey, I could be wrong. :)
OP replied. I don't think we need to blame ourselves, all the time, for OP's who don't return.
No, it's pretty common on any forum. I see it all the time, but it really does seem to happen more often on this forum than most of the others I frequent. I think part of it is the huge disagreement between posts.

Seems like on most forums the answers to questions tend to kind of agree and head in the same direction, but on the RV forum the answers really come from all directions. Maybe the posters just figure nobody knows what's going on. :)

And the disagreements between forum members are really mild on this forum compared to some of the flame wars that go on elsewhere. Some of them are really vitriolic.
CabinetmakerII
Explorer
Sep 06, 2014
gbopp wrote:
Consider something like this to Backflush Your Tank.

Also, try The Geo Method to keep your tanks clean.

Wow! Interesting Geo Method article.
darsben
Explorer II
Sep 06, 2014
drillagent wrote:
Ok, so I took some advice from here and flushed the tank until nothing else came out. Then I turned on my Iphone video camera and taped it to a yardstick and stuck it down the toilet. Very interesting. There isn't any mound or large piles. There's a lot of residual gunk on the tank walls. The pipe isn't exactly on the bottom, so it has a bit of a lip. Hence why it isn't completely emptying. But the most interesting part is that the pipe isn't at the end of the tank (facing the side of the trailer). It's actually at the side of the tank (facing the back of the trailer). Right by the toilet. So when it does flush, the dreaded mound of death goes down first.

So, here's the plan. I went and got some RV Rid-X at Walmart this morning and I've re-filled the tank to about 2/3 full. I'll let it soak overnight. When I leave in the morning, I'll tip the trailer back and flush it out again. Then I'll fill it back up with some calgon and detergent (Geo Method) and let it soak in storage for about a week. Does that sound like it will work?

Sounds like a plan to me.
2oldman
Explorer II
Sep 06, 2014
fj12ryder wrote:
But hey, I could be wrong. :)
OP replied. I don't think we need to blame ourselves, all the time, for OP's who don't return.
Big_Katuna
Explorer II
Sep 06, 2014
I don't get the mean spirited comments either. Contribute positive comments or move on.

I like the camera idea. I think I'll try it with my mother-in-laws iPhone.:)

Camping World sells a flexible tank cleaner that connects to a garden hose that has nozzles at various angles. You run a garden hose thru the window and spray the walls with the valve open. You can buy a flex hose for your power washer too. Made for cleaning gutters.

About once a year I run the flex spray up from the dump valve after I am sure the tank is very clean.

Go ahead, say mean things.

There is a nationwide franchise operation called All Pro Water Flo that has a tank cleaning process using a specially designed high pressure washer with a multi head sprayer they slide in through the valve with a camera. It blasts all the minerals that build up on the sensors. I saw them do an RV once and was surprised by how much stuff came out of the gray tank.
big_buford
Explorer
Sep 06, 2014
May want to inspect your tank supports. I had to reinforce mine to ensure complete drainage. Once the bottom is bowed its done. Not worth the effort to jack up everytime, just fix it and be done with it.

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