Black Pyramid

Black Pyramid

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Black Pyramid

Question presented on the Yahoo discussion group ALLABOUTRVING

I emptied my tanks. Sensor said 1/3 full. I thought they were completely emptied. Just two adults using jugs of water to flush.
Maybe 5 gallons so far. Two days later Sensor says full. Also we have a drip drip from the part connected to the trailer. The cap is tight


Jan, you have multiple problems that each need to be addressed so let's break down the problems and discuss each:

1. What the sensor says. RV Tank Sensors lie. The tank sensors on RV'S are probably the most unreliable gadget that has ever been sold. If not the most unreliable it is certainly in the running for being the most unreliable.

Many/most experienced RV'ers do not pay attention to what those RV Tank Monitors say. Most of us that spend a lot of time in our RV's know how
long we can go between dumps. Just like I know how long I can hold my breath.

I am sure dozens of well intentioned individuals will give you dozens of "home grown" remedies that they guarantee or have heard will get those
tank sensors working again.

OK, that problem should be behind us.

2. I am not real clear on what part is drip/dripping but I assume the drip/drip is coming from the sewer cap.

A DRIP coming from your sewer cap is NOT good. It is BAD, very bad indeed.

In order for your BLACK (sewer) tank to properly flush it has to have a lot of water to carry the solids away. If all your water/liquids are
dripping out then what is left behind in the black tank is your solids. Without liquid those solids will become as SOLID and HARD as concrete.
This mass of solids left behind will become the dreaded BLACK PYRAMID.

If you do have the dreaded BLACK PYRAMID you indeed have a problem and the indications you are getting from your tank sensors may be correct.

Over time if you have not been getting a good flush to get those solids out of your black tank you may have a tank full of those solids (the black

There is a good indication, to me at least, that you may indeed have a tank full of solids. The two clues are:

a. You are flushing with jugs of water. That indicates to me that you are NOT using nearly enough WATER/LIQUID to get a good flush when you
empty/dump your tank.

b. The drip that you describe coming from your sewer cap is effectively draining what little liquid you did have in your tank so that when you do
attempt to flush nothing really takes place. Thus what you have is a tank so full of solids that you can only add a few gallons of new "sewage"
before it is full again.

3. It goes without saying that you need to get that drip fixed immediately or sooner.

Now lets discuss troubleshooting your problem:

First, you need to be connected to a sewer so that you can dump.

Then, fill your black tank with water. How much water are you able to put into your black tank before it gets full? How big is your tank?

You will know your black tank is full of water when the water starts coming up in the neck of the toilet. You can see that by looking down the
open toilet hole.

If you have a 35-gallon black tank and you think you put 35-gallons of water in the tank then you probably do not have a lot of solids in your black
tank that case you would be LUCKY.

If on the other hand you have a 35-gallon black tank and you are only able to put say 5- gallons of water into the black tank then ............. you
have a major problem. That would mean that you have 30-gallons worth of solids taking up room in your tank that are not being emptied/dumped......those solids just reside in your tank taking up space.

Another thing you might do is open the toilet valve so that you can look down the hole into the black tank. Oh yea, this is fun. VBG

With a flash light look down into the black tank. What do you see? Think positive, you want to see the bottom of your black tank.

Find something like a broom handle or other such stiff/rigid object and poke it down into the opening and see if it hits the bottom of the plastic
black tank or does it sound like it is hitting something else. If the broom handle is hitting something that is not the bottom of the tank is it HARD or is it softer. Black pyramids have been reported to be as hard as concrete. Obviously, some may be softer.

If you have a problem with solids in your tank you may have to fill the black tank with water and hope that the solids will become soft enough to
eventually be able to flushed. Of course after letting the tank sit for a few days while full of water you may need to come back and jab that pile
of solids with something (that nasty broom stick) or something else that may break up and dissolve some of the problem and allow it to be flushed
out when you dump. You may have to do this over and over and over until you get most or all of the solids out.

Now lets discuss the DRIP you have.

That drip is caused by a malfunctioning slide valve. These are cheap and easily replaced. Well, it is relatively cheap to purchase the valve. And
the valve is rather easy for you to replace. All bets are off if you pay an RV repair place to replace your valve. They do not like doing that job
any more than you are going to like it and remember it is your "stuff" dripping out of that black tank. VBG

To keep that drip from happening you need to be using more WATER with each flush. That valve is dripping because solids have gotten in the way and
and are allowing water to drip by.

Watch this video:

and you will see how solids get into the slide valve and cause the valve to leak.

and let us know what you find as you troubleshoot the problem. Your feedback will help us as we attempt to help others in the future.

We would love to hear from you......just put "info" in the place of "FAKE" in this address:

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