I recently (August) bought a used 2017 Catalina Coachman. Found out about a week later that the black tank valve had been left half open. Currently I am having to dump the tank about every two days (there are two of us in the trailer), and take a sprayer wand to it once a week, at least. I'm looking for suggestions of products that might help with this situation, or cleaning techniques to get rid of residue that I'm pretty sure has been built up since before we bought the trailer.It is supposed to have a 30 gallon black tank, but, after the last time I dumped the tank, I poured about 10 gallons of water in, and it was reading full again.

The primary purpose of the idiot light gauges is for the salesman to explain about the great monitor system. Why do you think it's full with 10 gallons?Fill with water and drive. Add bags of ice cubes and drive.

Use a flexible hose wand and flush for an extended time.

I know the sensors are only suggestions, when they work, but when I can get the sensor light to show 1/3 full, put two 5 gallon buckets of water in, and it shows that it is full, I'm pretty sure that's an indication (as well as shining a light into the toilet with the valve open, and seeing liquid just below the floor). As for the flexible hose wand, that is what I use.

TexanSon wrote: … (as well as shining a light into the toilet with the valve open, and seeing liquid just below the floor). As for the flexible hose wand, that is what I use. If you really have water to just below the floor with the valve open, then suit up; because you are going to get really wet, dirty and create a big mess.

Sounds like you have a large version of the poop pyramid going on. Someone left the black tank draining during use. Some form of pooper-mache.Choose a good bacterial poop/paper cleaner and put that in the tank, fill it with water, let it set a few days, take it for sloshing drive to really stir it up and let it set a few days more. THEN dump it and wand it out.So far my fav cleaner is Happy Camper.Many swear by the ice cube trick. Best bet there is to make your own large solid cubes so they have chance to knock things around and apart before melting. But if the contents isn’t softened a bit before, it won’t work that well. Also when using ice cubes you don’t want a tank full of liquid. You want the cubes knocking around the bottom.IF you have a direct drop into your black tank, you could lightly use a pressure washer to break the pyramid apart. The reason I say lightly is BACKSPRAY and high pressure water could eat into the tank plastic.

Black Tank only holds 1/2 to 1/3 of capacity | Good Sam Community

ktmrfs
Explorer II
Sep 20, 2023
Vintage465 wrote:
Glad it looks like you're at the end of the issue. I've found a few things that affect black tank performance..........if you can call it that! 1st.....forget about the sensors, as mentioned, they're a sails pitch and will need constant cleaning from jet pressure to even be in the ball park. 2nd, make sure you figure out your "water to solids" ratio. Meaning make sure you're not concerned about conserving water that there is not enough water to help disolve/break-down solids and toilet paper. 3rd, make sure you're dumping on a reasonabley level or leaning to the dump side surface.

On the "water to solids". When we boondock, DW and I go about 7 days and the 32 gallon tank which uses the sealevel gauge system is about 50-60% full. Be careful with TP. the tank then get sloshed around till we either get home or to a dump station (usually home). Doing this it does require the use of the tank rinse system to clean the tank, but we've never had any other issues. Even with 4 adults and 2 grandkids we can go a week before filling the black tank.
Vintage465
Nomad
Sep 20, 2023
Glad it looks like you're at the end of the issue. I've found a few things that affect black tank performance..........if you can call it that! 1st.....forget about the sensors, as mentioned, they're a sails pitch and will need constant cleaning from jet pressure to even be in the ball park. 2nd, make sure you figure out your "water to solids" ratio. Meaning make sure you're not concerned about conserving water that there is not enough water to help disolve/break-down solids and toilet paper. 3rd, make sure you're dumping on a reasonabley level or leaning to the dump side surface.
TexanSon
Explorer
Sep 20, 2023
Update, maybe final one for this thread.

First, thank you everybody for the advice. I've been using Unique in the tank for the last week. Dumped the tank last Friday, and then today, 5 days later. Based on limited visual inspection, the tank looks pretty good (for a black tank), and I think our problem, now, is just that we are slightly off kilter. I've got a few issues that I need to work out inside the trailer before I can even think about trying to get the level better, but I will definitely be high-siding the trailer when I can move it.

Again, thanks, everybody!
ppine
Explorer II
Sep 17, 2023
The sensors are notoriously inefficient. Make sure you use TP made for RVs that breaks down quickly. The special devices for tanking rinsing work. Instruct your companions to minimize the use of TP.
TexanSon
Explorer
Sep 17, 2023
Keeping an eye on that. Added Unique to the tank Tuesday, dumped the tank on Friday and added more. Going to add some more this morning, and hopefully not have to dump the tank until at least tomorrow.

Thanks for the advice!
dave54
Nomad
Sep 17, 2023
Like the others noted, the sensors never work right. I will flush and clean the tank, and after about the second flush the sensors all read full again.

I can tell how full it is by the smell when I flush. When I detect the tell-tale odor, it's about 3/4 full and time to plan a dump.
Bionic_Man
Explorer
Sep 13, 2023
Echoing the chorus of don’t trust the sensors. They are never accurate.

When I had the pyramid of poo I used rid-x.
msmith1_wa
Explorer
Sep 13, 2023
Typically there are three sensors on the holding tanks.They are typically spaced at 1/4, 1/2, and 3/4 of the height/depth of the tank. Monitor panels are typically labeled 1/3, 2/3, and full. With this setup when the monitor panel shows full the tank is actually 3/4 full. Or leaving 1/4 of the capacity remaining.
midnightsadie
Explorer II
Sep 12, 2023
never trust the sensor there wrong from new not a good way to check your problem. pull the commode and get a good light . might pay to pull the tank and clean.
rhagfo
Explorer III
Sep 12, 2023
schlep1967 wrote:
Go watch this video National RV Training academy. I would go with the liquify brand based on his test.
In your situation it may take a few treatments to get it cleaned out.

I was in your situation, but not full time used about 1/2 box of Rid-x added about 10 gallons of warm water and let it sit for a month.
In your case I would use a heavy dose of either of the two products listed. Go as long as you can before dumping, the use a wand to help clear out the residues.

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Black Tank only holds 1/2 to 1/3 of capacity

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