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

[TexanSon]

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.

[TexanSon]

schlep1967: Thanks for the video. I'd heard of both of these products, but didn't have any real reference for how well they worked. I'll look into these.

Thanks, everybody for the info.

[opnspaces]

Maybe dump the tank and look down the toilet before you add any water. Can you see the bottom of the tank or is there a buildup?

[nickthehunter]

Just because you empty the tank, doesn’t mean the sensors will read correctly after emptying. Even if the sensors are working properly, it may take awhile before they read the level correctly. If one or more of the sensors is not operating properly, they may never read correctly. Best bet is a flashlight and the wet mark on a stick dipped to the bottom of the tank to verify level in the tank and sensor readings.

[CA_Traveler]

Try a wand with a very directional and horizontal flow and rotate slowly. Use one of the cleaners and the wand to cause water movement. Let it sit and redo several times

Another option is to come in from the drain, with appropiate funnels and hoses etc.

When full insert a dowel in the toilet, make sure it bottoms, mark the floor height, measure the water and mark and see how that compares to the expected dimensions per the mfg or another owner. Also check when the tank is empty.

[TexanSon]

I have heard about the ice cube technique quite a bit, but we are unable to move the trailer at this time. For one, our trailer is at the upper limit for our truck ('07 Ford F150), and the fridge, which is a replacement for the one that didn't work when we bought the trailer, was not secured into place when they replaced it. We are living full time in the trailer, as we have no other place to live.

It is Tuesday, 12 August as of this post, I just dumped the tank Sunday night, the 10th, and the sensors, which has shown 2/3 as of Sunday, are showing full again, so I am going to dump the tank and take the wand to it again. Once I'm done, I'll check the sensors again, fill the tank and see what kind of capacity I come up with, again, and post an update. I am using a Camco flexible wand hose, if that matters.

In the meantime, any suggestions for cleaning the tank while it is stationary would be appreciated.

Update: After dumping and wanding the tank, filling with about 20 gallons (I was shocked), dumping again, and filling with 5 gallons, the sensor is showing 2/3 full again.

[schlep1967]

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.

[Boomerweps]

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.

[nickthehunter]

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.

[TexanSon]

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.

[CA_Traveler]

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

[CA_Traveler]

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.