Black and grey tank sensors

The common response to this is: forget about those sensors. They rarely work properly.

I use the sensor lights to let me know how clean my tanks are. If I am hooked with my drain hose, I will fill and rinse my tanks - normally about 3 times, and when all the sensor lights read empty, I feel the tanks are clean "enough".

If your sensors have a film of **** that has been dry for a long time, it may take more than a few rinses.

Ice cubes, water, and driving around may help some on getting the senors cleaner.

Black tank, shine a flash light down the hole...my gray tank sensors reading are petty close.

2oldman wrote:
The common response to this is: forget about those sensors. They rarely work properly.

You can obsess over cleaning them only to have them gunk up next time tanks are used.

Tank level sensors like battery level monitor are just 'do-dads' for salesmen to point out. Oo-Ahh.

Toilet 'burps'----time to dump black tank
Sink/shower draining slower....time to dump grey tank
Water pump goes 'brrruup'....need more fresh water


After a few trips you will get a handle on how long before each each tank fills up.
Dump when full

For me, rinsing out the tanks (using a spray wand for the black tank) and letting them sit makes the sensors work properly. Putting some cleaner like dishwasher detergent in the water and letting it sit and slosh around would probably also do a nice job...or you can look up the "GEO method" for tank cleaning here for a rather more complicated but apparently quite effective tank cleaning regimen.

There are a number of people who say the sensors never work reliably and hence are useless. I find mine actually work fairly well most of the time and I do find them handy, though not essential. I wonder if the people who say they're useless say that because they've never had ones that work consistently; it strikes me as perhaps the attitude of someone who has a broken gas gauge and says that the gas gauge is not very accurate and you can always figure when to gas up based on mileage since the last fill-up. Those are both true statements, but it doesn't mean that a gas gauge, or a holding tank gauge, is not also handy.

I always figure how long we can go based on experience. However, my gauges work very well and seldom plug up. I never use the backflush system except at the end of year and I'm going to winterize.

The only treatment we use, never have had any smell, is from Unique - DigestIt. A natural treatment and it will dissolve all items keeping the system flowing well.

OK now that I've said this it must be time for me to be attacked. Go for it.

Sounds like the previous owner(s) didn't take very good care of their black tank. Yes, sensors can be troublesome but also can be fairly accurate if the tank is subjected to a procedure that will prohibit build up on the sensors.

I have found the best way to accomplish this is to empty the tank and flush out prior to traveling. I put about 5 gallons of water in the tank along with a cup of liquid laundry detergent (I use Oxy-Clean) and a 1/2 cup of Calgon water softener. While traveling to my next destination, the solution will slosh around in the tank "loosening" any residue left in there. Upon arrival at my destination, I'll drain the tank once more and put another 5 gallons back into prior to using the toilet.

This procedure has worked for me will all my rv's from our first single axle trailer to our 44' motor home and I highly recommend it.

In the OPs case, this procedure might take two or three trips to eventually get everything off of the season.....but it will work.:C

Hope this helps

Ron

You can try all kinds of new-fangled ways to try to clean the sensors, but the easiest and simplest is to simply drain the tank completely. Then add about 5 - 10 gallons of water. Now dump a couple cups of dish washing power down the toilet and go for a 30 minute drive! Once you get the camper back home, drain the tank again. Not only will it clean the inside of your tank, but it will also clean the sensors. If this does not work, then your sensors are probably shot!

If you want to use Dawn Dishwashing liquid down the toilet instead of laundry soap, Dawn works VERY well also. Pour a 1/4 bottle of Dawn into the toilet with about 5 - 10 gallons of water and go for the drive! Clean as a whistle! And very safe and sewer / septic tank friendly too!

The problem is not the sensors being dirty but is due to the tank walls being gunked up and fooling the sensors.

Even the non-contact sensors on the outside of the tank can be fooled if the walls are cruddy enough. SeeLevel even points this out on their web site.

The SeeLevel web site says "If sludge buildup in the tank becomes extreme the gauge will cease to operate (the tank will always read empty), so by monitoring the signal level the tank can be cleaned before the buildup gets excessive".
From HERE

Anything you do to help keep the tank walls clean may help.
Flushing, adding some detergent and water before you drive for a day or so might help.

I have the TrueLevel non-contact system that Winnebago went standard with in 2005 and right now my black tank reads full when empty. The gray tank shows 2/3 full when empty.

Over the eleven years we full timed I tried everything people say will work and nothing worked.
If I pressure washed the inside of the black tank (have done that twice), the level would be measured normally for a few months and then start to lie.

I think the problem is worse for full timers and that may be why some weekend or short term campers find that detergent or some other method works for them.

I ended up just dumping it every ten days and didn't worry about it anymore.

3-4 oz of Dawn after every dump add water and the ride home keeps them clean and accurate on my 10 year old MH.