Cleaning the grey tank sensors

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JayArr

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Mission British Columbia Canada
Hi All

I converted my Black tank to those Horst Miricle sensors and they work great, no more false readings.

Unfortunately the location of the grey tank sensors prevents me from converting them and they don't read right. I'm sure there is a coating of sludge on the walls fouling up the accuracy.

Has anyone ever tried blowing out the sludge between the sensors with electricity?

I'm thinking that if I disconnect the sensors from the monitor so they are isolated and then apply a voltage between two of them the current will flow through the sludge and blow it away. If it works it would be a cheap and effective way to keep the system accurate.

Does anyone know if this has been tried before, an I repeating an idea already shown to be unworkable?
 

JayArr

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Mission British Columbia Canada
I thought I'd start with a 12V battery, if that doesn't work I can step up to a 24V at 7A power supply I have on the shelf.

I suspect it will take a fair amount of current to burn/blow/remove the sludge between two sensors so my bet is that the low voltage may work best.

I figure I can use an ammeter to monitor the current draw and when it reaches zero the sludge path has been removed.
 

Pgh_AL

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Pittsburgh
When i first got my coach gray or black would read correctly after a few rinses with clean water and dumps they are almost corrected . The gray is perfect the black is about 85% . Couple more rinses and dumps ought to do it .
 

Ex-Calif

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I can't see anything but a really high amount of current doing what you want it to.

I have been noodling an attachment to my pressure washer to see if I can snake a spray head into the tank from the bottom up for the grey tank.

The blank tank is easy to access from the head but the grey tank has too many traps to go in from the top.
 

Benson

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North Tonawanda, New York, USA
I don't know how long this has been going on but there shouldn't be anything in the gray tank except mineral deposits and soap sludge. I would fill the tank with distilled water a cup of oxiclean or boraxo and add half a gallon of white vinegar and let it sit for a couple of hours or drive around and dump at the next stop and then check it and repeat if necessary. The vinegar will disolve and breakup themineral deposits and the borax should do the rest. I definately wouldn't go the way of electrical 'blasting' you'll distroy the sensors.
 

NY_Dutch

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Where our wheels take us!
The "sensors" in this case are little more than screws sticking into the tank at various levels. My concern with the electric "blasting" idea would be the amount of current needed to do any good, and how much heat would be generated where the screws pass through the plastic tank wall. Switching to one of the tank level monitoring systems that use external sensors might be a more practical solution, albeit a more expensive one. Mopeka has a $70 fresh/gray tank ultrasonic sensor that's read with a phone app.

 

jackiemac

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Scotland
I can't see anything but a really high amount of current doing what you want it to.

I have been noodling an attachment to my pressure washer to see if I can snake a spray head into the tank from the bottom up for the grey tank.

The blank tank is easy to access from the head but the grey tank has too many traps to go in from the top.
You need a jetter hose....

See this post on how we clean our black and grey (shower only as too sharp a bend for kitchen one).

Steve puts the jetter hose in via a vent in the kitchen cupboard. He unscrews a cap off a pipe.

 

Kirk

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Full-time , Escapee
Has anyone ever tried blowing out the sludge between the sensors with electricity?
As a 40+ year career electrical repair tech, let me suggest that before you try this find a firetruck that will standby next to the RV so that they can be ready to put out the fire that you will probably cause. They will also be ready to supply you aid if the battery you use should explode!

Rather than doing something so dangerous, why not try cleaning the inside of the tank? If you fil the tank half full or so and then use one of the detergents suggested, drive around for a while and then dump. I have used laundry detergent in that way many times but the very best product that I have found for tank cleaning is Trisodium Phosphate, available from Amazon.
81lxDCcrHPL._AC_UL320_SR320,320_.jpg
 
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Ernie n Tara

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May 16, 2009
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Ft Myers, FL
I think this is a really bad idea! The best you can hope for is that the sensors heat up and melt holes in the tank. I'd also expect the goop to bake onto the sensors like a rock.
After all, you've got the shower backup to tell when its full. Or just leave it open.

Ernie
 

Gary RV_Wizard

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At our Silver Springs FL home
Try filling the waste tank with water and a dose of cesspool enzyme treatment such as Roebic K47 or a drain field cleanser such as K570. Let it digest for 2-3 days and then flush. If the problem is slime, the bacteria will probably eat most of it away.
 

JayArr

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Mission British Columbia Canada
OK, good suggestions. I filled it with 40 gallons of warm water yesterday and put one of those detergent pouches in each sink and two in the tub. It's been sitting overnight. I'll empty it today and see if that restores operation. If not I'll try TSP or RidX

I don't see it heating or catching fire. Really now, how is slime inside a wet tank going to catch fire? The idea is that as soon as you hook up the power source the slime will get blown apart like a fuse link under short. I guess the problem may be that it just slimes back up the next day.

I wish I could get a jet stream up into the grey tank but the plumbing is too twisty to get a reliable clean that way. I do have the clear Rhino attachment that allows a hose to connect and shoots a stream of water into the tank but that only cleans the black tank. It works very very well on the black tank but does nothing for the grey.

I've looked at some of the ultrasonic systems but i don't carry a cell phone on vacation.
 

Ex-Calif

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May 15, 2020
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You need a jetter hose....

See this post on how we clean our black and grey (shower only as too sharp a bend for kitchen one).

Steve puts the jetter hose in via a vent in the kitchen cupboard. He unscrews a cap off a pipe.

Nice tip - thanks. I already have all the bits except the jet hose. I've put it on the wish list.

I did add (like it seems Jay has) a clear backflush elbow to the system. Now that I am a liveaboard the routine has been to close the grey tank valve a couple of days before flushing out the black tank so there is grey water to flush the black stuff out of the ground pipe into the sewer.

With this backflush elbow I don't have to save up any grey water. Last time I dumped I ran the hose until the black pipe was running clear but it really doesn't add a ton of water into the black tank. I like the idea of the jet hose.

I'll also scout around and see if I can find the grey vent and see if that has any easy access.

flush elbow.JPG
 

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