Black and grey tanks reading 3/4 when empty.

[Brew Crew]

We just bought a used 26 DS and the holding tanks are reading 3/4 full when they are empty. Is this just sensor issues or is there something more. How can I check this??

[geotex1]

You're going to need to work to clean the gunk off the sensors. If you search, you'll find many posts about this here and on every single internet RV forum in existence! There's no single fool-proof way to clean them, but you can start with commercial products for the task. Try the cheapest way and keep going till they read.

BTW - there are commercial holding tank cleaning services that will get your tank spotless and sensors clear, but they aren't everywhere and can be spendy.

[Brew Crew]

I just started search. I did find some about using ice cube and filling with water then going for a drive. How effective is this and could it damage anything?

[geotex1]

Personally I have had success with the old ice cube trick, but it's very subjective and there's some decent study on Youtube that shows not so effective. Plus, you're not getting cubes into the gray tank.

The big unknown is you have no idea how the previously owner kept the tanks, so could really take you awhile to get them in shape. You're going to get lots of opinions on what to do, but I will tell you how I have worked with any used camper holding tank and you decide from there. I more or less subscribe to the GEO Method of holding tank care, which stands for Get Everything Out. Get yourself some Calgon water softener for laundry use and Dawn dish soap in the original blue formula. Put a cup of each into each holding tank - direct through toilet for black and shower drain for gray. Then fill your holding tanks halfway (look through the toilet and you can guess using a bucket to fill the gray pouring into shower drain). If you can fill with hot water, it'll work better for this initial go. Then go for a nice drive with lots of bumps and turns to slosh around. Come back, fill up your tanks to full and let it sit 3-4 days and then drain. Repeat.

[fonzie]

Ice cube not effective as far as I'm concerned. Use RV digest as in this thread...

http://www.forestriverforums.com/for...-it-21920.html

https://www.youtube.com/watch?v=iH6acEmqvcw

[camper1999]

I put a cup of dishwasher soap with a few gallons of water. I do this before a long trip and it washes off the sensors. I have done this on numerous trailers. Never had a problem with sensors

[BigTJohn]

Remember that water is the universal solvent. Use more water than anything else. Only use chemicals when absolutely necessary. Only try the tank cleaning chemicals after letting water really soak into the contents of the tank and the dirty sensors. If you can, allow the water to sit in the tanks for at least a week before draining. Then try a rinse of the tanks. One of the black tank rinse wands that reaches into the tank from the commode will do wonders for the sensors plus the rest of the tank. Using it on the gray tanks will be problematic but if the shower drains are straight into the gray tanks, then removing the shower drain screen may help as well getting the wand into the gray tank. Just some stuff I have tried on different trailers and boats.

[Brew Crew]

Thanks everyone for the advice. I will post when it stays above freezing at night and after summerizing.

[Rockwoodjoe]

My brother laughs at me when I tell him that my TT has a yellow tank and no black tank. You figure it out. It does solve the clogged sensor issue as long as the park has facilities for you know what.

[Still Kickin]

Add this concoction (assumes tanks are empty) to the black and grey tanks. 2 cups liquid water softner (calgon) cheapest @walmart. (You have to look close for it as not much is sold so it has a small shelf space). 1 cup Liquid laundry detergent, 1 gallon warm to near hot water. I have been told you can get a cheaper version of calgon at one of those dollar type stores. The total volume added needs sufficient splash factor inside the tank, so as to clean up the sensors.

Ideally you should let the mixture set 24 hours before flight. Then drive/pull to next destination, then after sufficient splashing, fill tanks full and dump.

The way this works is, you need to break up the film/crud built up on your tank sensors, so they don't give you your current false reading. If you get good results, do that every now and then to minimize the crud buildup. Good luck.

[OldCoot]

Super Clean mixture works wonders on removing crud in tanks. About a quart and fill the tank and let it set for 2-3 days minimum. The longer soak, they better.

[4mula1fan]

Originally Posted by Rockwoodjoe

My brother laughs at me when I tell him that my TT has a yellow tank and no black tank. You figure it out. It does solve the clogged sensor issue as long as the park has facilities for you know what.

My theory exactly.

[flugelboneman]

And be sure to buy yourself one o those handy dandy see-through elbows that connects to your sewer outflow. There are few things that give you a greater sense of power than seeing all those lumpy things rushing through your see-through elbow. Before I started using one, I had assumed my tanks were empty. Little did I realize how wrong I wuz until I was able to see what was exiting. Another blessing is the built in black tank rinse.

[derek6669]

I had the same problem when I purchased my 2008 Sunseeker, tried the ice cube method it didn't work. In surfing the net, found the Geo Method, and after 2 treatments, started to see improvement in the sensor reading, by the 3rd treatment sensors were working correctly. Suggest you treat the black tank and the kitchen grey tank, the shower tank get's enough soap from showering to keep the sensors clean. Check out this site. https://sites.google.com/site/cbruni/

[robbdrell]

A rv seminar I attended recently recommended to use vinegar / water mixture. Maybe worth a Google sear. Presenter said been doing it for 3o yrs. I guess it's cheep. Will try it this season.

[Stepheng1]

This is for Still Kickin,

Your Idea about cleaning the B G tanks has brought new light for me.
My RV has only 2000 miles on it and my black tank kept reading full when it was empty. Tried you approach and it works, thanks a bunch.

[Witch Doctor]

Originally Posted by Brew Crew

We just bought a used 26 DS and the holding tanks are reading 3/4 full when they are empty. Is this just sensor issues or is there something more. How can I check this??

Sensors are always off, the best way is to use it and see how long you can go before dumping. I know that just the 2 of us I need to dump every 5th day for black and 3 days for gray if we use the shower or 4 days if we don't. Kitchen gray every 3 days.