Seneca black tank

[Dchafe]

Have been out for the week for our first trip in our 2020 Seneca. The black tank doesn’t drain all the way. Any suggestions? I’ve added extra tabs and water. I’ve also used the flush system. The psi guy said no one uses the macerater system unless to pump up hill. I’m on a level site. Any suggestions ? Thanks

[Robbbyr]

Are you certain the tank isn't draining or are you just going by the tank level indicators?

[Cavie]

tank indicators are from the same school as used car salesmen.

[Mark S]

Take a flashlight and look down the toilet with the water turned off. As Rob said, it may be empty with false indicator light. Unless there is a blockage there is no reason the tank will not drain.

I like having the macerator. If I do a one nighter in a park, I will use it to drain gray water in a hurry. Sometimes it’s just easier to use and it’s a good idea to exercise and flush the pump periodically.

[Dchafe]

I did look down the toilet. Looked like it wasn’t empty. I forgot we have the HJ and the black tank is smaller so maybe it just drains quicker.

[Cavie]

What is the HJ ? Model # ?

[EA37TS]

Originally Posted by Cavie

What is the HJ ? Model # ?

HJ is the floorpan e.g. 37HJ, 37TS, 37L, etc...

[EA37TS]

On our last outing I found that multiple black tank. flushing are required to get everything out of the tank on our 37TS. During a couple of the flushing a small piece of TP would hang up on the 1/3 sensor and indicate a non-empty tank when the tank was empty.

What I did was use the black tank flush with the black tank drain valve closed and fill the black tank. Once full I would pull the valve and drain. Amazing how much crud is still in the tank after the third and fourth time of doing this.

Eventually the sensors started reading accurately.

[norty1]

Moderator note:
Just a reminder, since we don't have a seperate forum for Super C's, it's a good idea to put the name Seneca in any thread you start on the Class C section to alert readers that it is not a regular "C" as Dchafe did in his thread.

[RVermont]

I use the sanicon all the time. Others have completely removed the unit.

Depending on where the toilet feeds into the tank you might always see solution in the tank. These tanks are supported on the side tabs and the bottom floats in air unsuppported except for a chuck of polystyrene insulation. Thus the bottom is concave and holds between 1/2 to several gallons of solution. If you are relying on the gauges you might have issues with tank gauges. Either from wiring issues or soils built on the probe.

If I am hooked up at a site I open the grey tank and let that flow all the time. The grey solution will flow though the pump. The hose is actually designed to work as a trap and will keep sewer gases from coming into your unit. Once a week I close the grey tank and let it fill up. Then when I have enough grey I open the black and using the sanicon I dump the black. This only takes 30-45 seconds. Close the black and run the grey again using the sanicon pump. This will take a couple of minutes. Once I hear the pump speed change I shut the pump off and leave it till the next dump day.

I then put about 2 gallons of water down the black tank to fill the discharge piping. This keeps the tank from drying out and helps to keep any solids from settling in the piping.

One of the biggest things with black tanks is keeping enough water in them to keep the crud in solution and time allowing the bacteria to digest the solids. Of you are constantly dumping the tank you dont have enough solution to carry the solids away and then if you dont put water in they can harden and you can get the dreaded poop tower.

I only clean the tank at the end of the season. I dont see the need to clean it. I Just keep it charged with water.

[Grumpy]

Originally Posted by Dchafe

I did look down the toilet. Looked like it wasn’t empty. I forgot we have the HJ and the black tank is smaller so maybe it just drains quicker.

Depending on where the toilet discharges into the tank you may have a slight belly in the tank that looks like it is holding water.

[norty1]

I like to be reminded that they call it a Holding tank for a reason.

I never keep black water in mine long enough for it to digest the solids.

[Dchafe]

Ya it seems to empty and the black tank gauge shows 33% still in the system. Some great advise on here. Thanks so much.

[SloPoke]

Originally Posted by Dchafe

Ya it seems to empty and the black tank gauge shows 33% still in the system. Some great advise on here. Thanks so much.

You will learn to disregard the black tank gauge completely. Our black tank gauge is a combination of 'how many days of use since last dump' and the most accurate one is 'look down the toilet with a flashlite and see the level of waste in the black tank'.

We laugh at the primitive gauge in black tanks, as it still will show F when the tank is verified empty.

[McGintys924]

This is one of those posts that makes me glad I went with the composting toilet. I actually blew my sanicon hose apart three weeks ago trying to pump through a 10 foot garden hose. It was just shower water on me an the truck so not that bad. I can only imagine if!