Will Ice Cubes Really Clean Your Black Water Tank?

[dale farley]

We've all heard that driving after placing ice cubes in the holding tanks will clean any sludge from the sensors, sides and walls. This video shows the results of an experiment on this subject. I don't sell ice cubes, so I'm not biased either way! http://vimeo.com/107203617

[Grizz]

I don't know what he's trying to prove, but the theory behind ice in a holding tank (half full of liquid) is to dislodge solid matter from the protruding gauge sensors. I've never heard anyone claim it would 'clean' a holding tank and there's no way ice can do the job if there's nothing but the melting ice in the tank - the tank must be about half full. This guy's experiment is based on a misconception.

[dale farley]

Has anyone ever had favorable results for using ice to clean the sensors?

[Grizz]

Yes, but not the kind of sensors typically used in Prevost conversions. The ice cube method worked pretty well in the old plastic tanks that had a row of screws and wires down the side. The liquid in the tanks would cause a short across two sensors (nothing more than metal electrode through the tank with screws on the outside to attach the wires) making the panel light up to indicate a minimum reading. I.e: 1/4, 1/2, 3/4 full (typically)

When solid waste like paper got stuck across the electrodes a false reading would be indicated on the panel. Adding a bag of ice to a half full waste tank just before heading out on the road would usually dislodge offending solids from the electrode. This practice pretty much went the way of the Dodo bird when tank flush systems came on the scene.

[Joe Camper]

I pulled the holding tank out of my 85 xl when it was over 20 yr old to access the bus fuel tank sensor. A flat bottom tank in a bus that had way less than adequate service. It was clean as a whistle not even anything in the corners.

Now that I think about it with all the old plastic campers and canned hams ive took apart I've not yet found one with any buildup.

[Joe Camper]

I pulled the holding tank out of my 85 xl when it was over 20 yr old to access the bus fuel tank sensor. A flat bottom tank in a bus that had way less than adequate service. It was clean as a whistle not even anything in the corners.

Now that I think about it with all the old plastic campers and canned hams ive took apart I've not yet found one with any buildup.

[Gil_J]

I think Joe is on to something. There's not much that sticks to the plastic tanks. This might not be the case with other materials.

The ice thing is a common thought with boaters. The thought is the ice will break up the sludge if you immediately take the boat out and slosh the ice around. Boat tanks don't use gravity drains but rather use suction to empty the contents. Due to the method of draining some stuff is always left behind. In a boat, I think a 10 pound bag of crushed ice down the head can work. Of course, this should not be attempted with a vacuum or macerator head.