Fresh Water Tank Scrubbing

[Thane]

This is the second of five links that address my efforts to clean, and keep clean, my 17 footer fresh water tank.

This is the first link. http://www.escapeforum.org/forums/f8/fresh-water-tank-extreme-maintenance-7425.html#post134332

This is the next link. http://www.escapeforum.org/forums/f8/fresh-water-tank-bleach-injection-system-7427.html#post134334

As discussed on the first link, I decided the tank needed a good cleaning. This required cutting a hole in the tank. Cutting a hole was pretty easy, it’s only 1/8th inch thick plastic. The difficult part was figuring out if I really wanted to, how to patch it, and how to clean the tank. The first picture shows the view inside the tank via the hole I cut in the tank.

For a patch I decided to add a Camco Tornado Rotary Tank Rinser, of course I figured this out before I cut the hole. http://www.amazon.com/Camco-40126-Tornado-Rotary-Rinser/dp/B000BUU5TU/ref=cm_cr_arp_d_product_top?ie=UTF8
I had previously installed a rinser on a holding tank with good results. I will use the rinser to clean and sterilize the tank. More on that later.

I couldn’t find any internet discussions about anyone else using a rinser for this application but decided it was the best option for me. A nice thing about the rinser is the required 1 ¾ inch hole is a good size. Not big enough to be scary and not small enough to make it a waste of time. I couldn’t get my hand through it, but it did provide adequate access for tools. The second picture shows the hole I cut in the passenger side of the tank.

The rinser is removable and that will allow me to re-clean the tank if I ever suspect contamination. I am not worried about the plastic rinser contaminating the tank. I smelled it; it had no odor. I licked it; it had no taste. I listened to it; it didn’t say it wanted to kill me. I think it poses the same risk as using a plastic fork and is a much less risk then cooties in the tank.

I could have used a simple screw-on a patch, but what is the fun in that? If the rinser turns out to be a maintenance hassle, then I will install a simple screw-on patch. An adhesively bonded patch would probably not hold as the plastic is impervious to most chemicals and glue will probably not stick well.

I drilled a hole in the center of the tank (fore to aft), on the curb side, about 3 inches above the bottom of the tank as shown on the second picture. Because of limited room I tried a hand drill first but it was awkward so I switched to a 90 degree power ratchet with a drill bit adaptor. I could have put the hole higher but that would have made cleaning the tank more difficult so I am satisfied with location.

I removed the water pump inlet fitting and the drain cock from the other side of the tank to provide maximum drainage during cleaning.

I thought cleaning would be pretty straight forward, I was wrong.

I thought I could just blast the cooties loose and drain them from the tank. So first I tried a simple brass twist type hose nozzle like this http://www.amazon.com/Gilmour-Solid-Brass-Twist-Nozzle/dp/B00ZVKFBR6/ref=sr_1_2?s=automotive&ie=UTF8&qid=1459011722&sr= 1-2&keywords=twist+nozzle . I tried a variety of spray angles from a wide spray that was almost perpendicular to the surface to a concentrated high pressure spray that imparted a strong glancing blow. I was very surprised to see that this did not remove all the growth. Kind of disappointing to see that the normal sanitizing routine of driving around a bit to slosh bleach around the tank would not be very effective.

I then made a spray wand out of PVC pipe with small holes on the sides, pretty much like a black water tank wand. This produced a very localized, high pressure jet that I could aim directly at the cooties. This was also ineffective and surprising.

I then put warm water and dish soap into the tank and attached a wash cloth to a PVC pipe and worked it around the tank. This was effective and scrubbed the lower sides of the tank as well as the bottom. I then agitated the mixture to fill the tank with soap suds and after letting it sit a while I rinsed and dried the tank.
Although it was now clean it may have had a slight film so I decided to experiment a bit more…

I made the scrub pad shown in the third picture out of a nylon scrubbing pad, sheet steel and a bonded stud plate. It was almost square and small enough to get into the tank. It took a pair of needle nose pliers to get it out of the tank. It was heavy enough to provide a respectable vertical load on the scrub pad. I used ½ inch PVC pipe with a 90 degree elbow fitting to move the scrub pad around the tank. The 90 degree elbow fit nicely over the bonded stud so I could easily move the pad around the tank and provide some additional pressure for scrubbing. It was impossible to get the pad into the corners to the left and right of the hole without modifying the PVC pipe so I used a strong magnet (salvaged from a computer hard drive) on the outside of the tank to move the cleaning block on the inside of the tank. I partially filled the tank with bleach and water and scrubbed it for about 10 minutes.


The last picture show the rinser installed on the tank and the rinser hose fitting installed near the rear bumper. The hose fitting is just for convenience and keeps me from having to get under the trailer to install the fresh water hose when cleaning the tank.

To make the rinser more effective I came up with a bleach injection system that cleans the fresh water tank and hose as discussed on the next link. http://www.escapeforum.org/forums/f8/fresh-water-tank-bleach-injection-system-7427.html#post134334

The fresh water tank may be cleaner than it was when new. I will use the rinser and bleach injection system often. I flush the waste tanks every time we camp, why not flush the fresh water tank too? I think it will be pretty easy.

[Ron in BC]

Good work and an Interesting write-up.

I've had large boats for many years with aluminum, s/s, plastic and fiberglass tanks. They all had one thing in common, a 6" inspection and clean out hatch. So I've looked in a lot of tanks over the years. What I've noted is that mold starts to grow on the top surfaces when the tank's not full. The black debris you see on the bottom is likely the mold clumped up after its' been flooded with a fill up.

The nice thing about the clean out is that you can physically scrub the interior and get it spotless. While we have always normally had a separate fresh water supply for drinking, we have used tank water for everything else, including brushing teeth and have never had a problem. The way that I could tell that the tank needed cleaning was when tea made from it didn't taste all that good.

For the trailer we do the same as most but we do always add a touch of bleach each time we fill. So far the tea still tastes good.

Ron

[bouterse]

Ron : How much is a 'touch' of bleach?


Jack

[Ron in BC]

Originally Posted by bouterse

Ron : How much is a 'touch' of bleach?
Jack

1 or 2 teaspoons, nor enough to taste or smell.

Ron