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Sunday, January 3, 2010

Holding Tanks and Level Gauges

Today I dumped by black tank. Not a big deal, right?

We are full-timers...that means we live in our coach 365 days a year, having started our adventure in December 2007. For the first couple of months we had no problems with our holding tanks. Our 2008 Monaco Diplomat came with a macerator. For those that don't know what a macerator is, it's a device that you hook up to your holding tank dump and, by sending all material through a propeller looking blade it does 2 things...first, it turns solid waste into a slurry liquid, and second, it acts like a pump to force that slurry down the hose. The output hose is a 3/4" size hose just like your garden type hose. My macerator is rated to be able to pump the slurry material 200 yards horizontal and 20 feet vertical. That means you don't need to park your rig close to the sewer dump, and you don't need to carry 50 feet of stinky slinky hose. You can use any 3/4' garden hose up to 200 feet in length.

Back to the subject...after 3 months of living in our coach I started to notice that my tank gauges were no longer reading empty after I dumped the tanks. My first thought was that it was a one-off and the next time I dumped the tanks they would return to reading empty. But that didn't happen, in fact it got worse. Instead of reading 1/3 full when empty they started reading 2/3 full, and finally 3/3 full. I couldn't figure out what was wrong. My black tank has a sprayer and I used it every time I dumped, so how come the gauges aren't reading empty?

I went online to search for answers. Almost all of the responses I received said "Welcome to our world, our gauges haven't worked right for years". I thought, you've got to be kidding, my rig is only a few months old and your telling me this is normal?

I also received other friendly advice to try the Geo method or use water softener in the black tank. I tried both of these ideas but I wasn't able to get my gauges reading empty. The only thing I didn't try was putting ice cubes in the tank. Since my problem involved both holding tanks and there is no way to get ice cubes in the gray tank I ruled this idea out. While it may work for the black tank, I needed a solution that would work for both tanks.

While I was at my dealer getting maintenance work done I mentioned the problem I was having with my tank gauges. They recommended a modification to my black tank sprayer that enlarges the holes in the sprayer head that allows more water to spray into the tank. They also dumped some Thetford Level Gauge cleaner in my tanks and told me to dump my tanks as soon as we got back to the RV park and got hooked up.

From the dealership to the campground was a drive of about 40 miles on twisty roads. I did as instructed and was surprised to see both my tanks reading empty, and relief in knowing my gauges were working.

What have I learned from all of this? First, I have modified how I dump my black tank. You can't just open the valve, turn on the tank sprayer, let it run for 5 minutes, then shut it off and close the valve. I have found the best routine is to open the valve, turn on the sprayer, and when the tank empties I close the valve, wait 10 minutes to allow the tank to accumulate water, I also flush the toilet with a full bowl of water 3 or 4 times, then open the valve again and dump the tank. I continue this cycle until the gauge reads empty. Usually takes doing it twice, but I don't quit until the gauge reads empty. Once the gauge reads empty I close the valve and let the tank sprayer run 2 more minutes (to ensure there is water covering the bottom of the tank), then turn off the tank sprayer. I have been using this method now for over 18 months and my blank tank gauge still reads empty.

The gray tank is another story. When parked I usually leave the gray tank valve open since we have a washer/dryer and do loads almost every day. But while in Kansas I wasn't able to do this as the sewer hookup was higher than the tank drain. It didn't take long before the gauge wasn't registering empty after dumping.

I have discovered that the Thetford Level Gauge cleaner doesn't work as well when the coach is not moving, or if it's below 60 degrees outside. In Kansas I knew I had to drain the tank every day, so I didn't really need the gauge working. But when we got ready to leave Kansas I dumped the tanks and then added Thetford Level Gauge cleaner to both tanks and filled both tanks to about 1/3 full with water.

2 days later, in Amarillo, when I attempted to empty the gray tank I opened the valve and nothing came out...something was blocking the dump drain. When I snaked out the tank I found the problem. Apparently the Thetford Level Gauge cleaner combines with the leftover soap scum in the tank and causes some kind of reaction that makes the soap into a crystal type material. Because I didn't dump the tank after at the end of the 1st day, those crystals formed a layer of hard material when it settled on the bottom of the tank. Once I broke through the material it started draining, but I had to flush the tank for the next 3 days until I was able to see clear water draining from the tank. If you decide to use the Thetford product I recommend only adding it when you will be driving the coach, and, empty it the same day, do not allow it to sit overnight.

As a side note...if your wondering what I used to snake the tank...this is easily the best $10 I have spent for an item for the coach. It's called a closet auger. If you don't have one I highly recommend it. I have used it for the clogs on both my holding tank drains and my toilet. My toilet is not located directly over the black tank, so there is a 90 degree elbow below the toilet to the tank and I have had clogs in the elbow from flushes with not enough water to push the material all the way to the tank, about 10" from the elbow. I bought the 3 feet model auger, but they do come in longer lengths. My tanks are very close to my dump valves, but if yours are father away be sure you get the longer auger. In my experience you need to be able to snake all the way into the tank.

In closing I just want to say that my gauges continue to show empty after 2 years on the road. I use chemicals in my black tank to help with breakdown of solids, and no chemicals in the gray tank. I have also heard arguments against macerator's saying that because they dump the tank slowly you can't get the tanks clean. All I can say to that is I use my macerator all the time and have not had any problems keeping my gauges working and the tanks clean.

To anyone who has gauges that are not reading empty I hope you find this information useful in correcting the problem.

[June 2010]
A friend of mine highly recommends this product:

Would be nice to get some feedback from others on this post. I have linked this article on a few forums and I would like to know if anyone found this info useful.

Stay safe out there...