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DCMAC214 · 04-11-2023, 12:28 PM

Indicator light for grey water shows 3/4 full...all the time. Is there an alternate way to check the tank level?

Last two trips came home with (assumed) about 1/2 full tank warm water and with 3 laundry pods hoping the ride and soap would clean the sensors. No change.

Black water tanks no problem, just have to look down the toilet hole.

Duster73 · 04-11-2023, 02:03 PM

Hmm thats a tough one for me.

You could fill the grey tank up and then once it comes up the shower drain(or lowest drain point), then you know its more than full. Check to see if the level changes.

I know there should be a grey tank vent on the roof. Maybe run a small weight on a string to the bottom. Then see how deep the full tank of water is. Measure the height on the string and then look up your particular tank size for your rig. See if the height correlates.

I used about a half a bottle of dish soap in a half to 3/4 full grey tank. Drove 20 minutes to the campground and dumped. Couldn't believe the black crap that came out of the grey water. I know you did laundry soap, but just telling you what I did.

HopsBrewster · 04-11-2023, 02:15 PM

Gray water tanks get a lot of kitchen grease in them. I don't know of any laundry detergent that works well on heavy grease. Modern washing machines have a warning label saying not to wash greasy items. I suspect Dawn dish soap would work better, because it is designed to clean out grease. Give the soap and swish method another shot with Dawn.

Treetopguy · 04-11-2023, 02:48 PM

Quote:

Originally Posted by DCMAC214

Indicator light for grey water shows 3/4 full...all the time. Is there an alternate way to check the tank level?

Last two trips came home with (assumed) about 1/2 full tank warm water and with 3 laundry pods hoping the ride and soap would clean the sensors. No change.

Black water tanks no problem, just have to look down the toilet hole.

If it were me, I would use a heavier caustic than laundry detergent. Drain cleaners are heavy caustic. caustics are safe to use with plastics. They will slowly corrode soft metal such as aluminum or copper,etc. Heat also activates caustic to work better.
Be careful to use gloves. it also corrodes skin! Also,do not mix it with acid. That causes a heat reaction.

Sent from my SM-G950U using iRV2 - RV Forum mobile app

**hamm2018** · 04-11-2023, 03:02 PM

Quote:

Originally Posted by DCMAC214

Indicator light for grey water shows 3/4 full...all the time. Is there an alternate way to check the tank level?

Last two trips came home with (assumed) about 1/2 full tank warm water and with 3 laundry pods hoping the ride and soap would clean the sensors. No change.

Black water tanks no problem, just have to look down the toilet hole.

Just got to the point where we don't worry about the sensors. When the black tank is getting full, the toilet "burps". When the grey tank is getting full, the shower "gurgles" and then I dump.

Persistent · 04-12-2023, 08:04 AM

Quote:

Originally Posted by DCMAC214

Indicator light for grey water shows 3/4 full...all the time. Is there an alternate way to check the tank level?

Last two trips came home with (assumed) about 1/2 full tank warm water and with 3 laundry pods hoping the ride and soap would clean the sensors. No change.

Black water tanks no problem, just have to look down the toilet hole.

The plan you used is the one I also use. I expect you may have to repeat a few times to remove what ever is caked onto the sensors. Dawn dish washing liquid is what is usually recommended. I use waste gray water for the drive home. It usually has enough Dawn in it already.

I would not use caustic drain cleaners. The sensors most manufactures install are usually metal. The sensors may be chrome plated which would be OK with caustic. But, there may be exposed metal under the chrome that would undercut the chrome. Use caustic as a last resort.

twogypsies · 04-12-2023, 09:41 AM

If you start using laundry pods, etc. that, in itself, could cause residue on the sensors. There's a video out there on YouTube that deals with holding tanks. The guy made a plexiglass one and put it in the rear of his pickup. He added some food scraps and a little grease and filled it. As he drove around fairly fast and turned corners that water really didn't move move to agitate the contents. It just moved slightly. Your pods probably don't work either... not enough agitation.

We always wiped our plates & pots with a used paper towel or napkin before washing dishes. No coffee grounds down the drain either. We tried to dump when full; not half or lower. Never used any kind of cleaners. Absolutely no problems.

**pasdad1** · 04-12-2023, 09:50 AM

When my sensors were not reading correctly, I added 5 gallons of vinegar, and 5 gallons of hot water to the grey tank then drove several hours to next destination.

When at destination, I continued to let the tank fill normally until I felt it was close to being full, then dumped.

Seemed to work pretty well!

SergioP · 04-12-2023, 09:55 AM

I got nothing for cleaning the tank sensors. But….

Why after 40+ years do tank sensors not read well? How much more could it be to use a level sensor like a fuel tank has? Then the reading would be just like the fuel gauge, instead of the full, 2/3, 1/3, etc junk. For as much as an RV costs adding this type of sensor can’t cost that much. Sure the float part would need to be shielded from toilet paper and the other things in the black tank.

**Camp CA** · 04-12-2023, 10:20 AM

Quote:

Originally Posted by DCMAC214

.......Is there an alternate way to check the tank level?.......

We use the hamm2018 method. We augment that by adding a solution of lemon-scented pine-sol and calgon bath beads with some water to keep the tank and sensors clean espeacially while traveling per the method described here: https://kleentank.com/throw-away-you...-this-instead/.