Water tank cleaning

[csoule13]

The last time I emptied the water tank on my 27, the water had likely been in there for a significant amount of time. It was more science experiment than anything else. Finally got around to taking the tank out and bringing it home for a cleaning. For my fellow 27 owners, I'll do a seperate post with photos of what the V berth looks like torn apart. It's interesting.

What do folks use to clean these things out? There looks like there is a bit of gray or black specks on the inside, but nothing anywhere near as bad as expected. Also, the coper feed tube is tarnished, and the last little bit of water in the tank had picked up that odd neon blue color from it.

End result is not to have potable water, but something to be able to use for cleaning dishes, washing hands, etc. If I were go for something drinkable, I'd probably put a filter at the sink. But that's outside the scope of the project for now. And yes, new hose from the tank to sink connection will be part of this.

[Frenchy]

What I did to clean was load up the tank with sand and maybe a quart of simple green, then
capped the outlets. We swished the mixture back and forth for a while, turning the tank until it
came clean. I think the black inside was some form of mold.
After several fresh water flushes, the tank was reinstalled with new vent and supply hoses. - Jean

[sgbernd]

I found a high pressure garden hose pistol nozzle fits into the inspection port and can be aimed over most of the tank interior. I siphon all the water into the bilge, then used the pressure blast to dislodge the sediment, mildew, etc. Siphon all that into the bilge and repeat again and again until there is mostly nothing left that doesn't look like water. The baffles make this a bit more challenging. The siphon hose has a stiff wire attached so I can aim it at the worst accumulations. The tank is HDPE and the crud has a tough time sticking to it so mostly it just comes off. While not 100%, the result is pretty clean and is easier than removing the tank.

BTW, this is a great chance to test all your bilge pumps, float switch, etc. as they all get exercised. Since I advocate to test them every year, but run a dry bilge, cleaning a water tank is a twofer.

Steve Bernd

[Steve Laume]

I am heading down to winterize Raven's fresh water system today. I have always used the pressure pump to empty the tanks. Most of the time I manage things so there is not much left at the end of the year but it still amounts to a lot of run time on the pump. I never even thought of siphoning it out. Thanks for the tip. What I do after the water is mostly gone is to vacuum out what remains. Once I run the pink through the system I vacuum out what is left in the tank and use that to winterize the head and bilge. A small amount of water in the tanks always seems to grow the greatest amount of crud.

I drink the tank water but I have done a couple of things to make it palatable. First is rinsing in the spring and pumping out that water. Once it is clear of antifreeze, I clean the screen in the pre filter and install a carbon element in the whole boat filter. I found it far easier to mount an under sink filter, right after the pump so it treats all the water in the system than just the sink water. I suppose it depends on where you have more room as the filter can handle the volume either way.

I also got rid of the fill hoses for the tanks. Those things were nasty and you can never tell how full the tanks are when filling from the deck. I open up the hatch in the main salon and drop a hose in to fill from the inspection ports. You always know exactly how much water you have used and how much goes into each tank. I usually draw from both tanks but there have been times when I only use one side so I know I have one full tank. By filling through the inspection ports I can top off one tank without worry about overfilling and losing water out of the vent lines.

The carbon filter is is the key to great water from your tanks, Steve.

[bottomscraper]

Camco Spring Fresh

It's available at many camping stores and also from Amazon:

https://www.amazon.com/Camco-40207-Tast ... 000EDUTQS/

If you are in a place where you winterize the tanks with non-toxic antifreeze use this stuff in the spring after draining the antifreeze. It does a good job of getting rid of the antifreeze funk.

http://www.camco.net/spring-fresh-1-gal ... gual-40207

Starbrite has a similar product called "Aqua Clean Water Tank Flush" but it is typically a bit more expensive.

[csoule13]

Follow up - Since the tank was home, I filled it most of the way with almost boiling water. Let sit for a spell, then got in there with a stiff toilet brush and scrubbed. Not a perfect soution, but I'd guess about 85% of whatever gunk was in there is gone.

Since the tank has been empty for two years, has now gotten a good soak in very hot water, is getting new hose run to the sink, and isn't going to be used for drinking, it's as good as it needs to be. I really wish the PO hadn't just let the stuff stand season after season. As far as boat projects go though, this was pretty easy.

[ghockaday]

It can be sanitized with Potassium Metabisulfite. It is what I sterilize my wine making equipment. Easily gotten on line. Dennis

[BrandonL]

I found a high pressure garden hose pistol nozzle fits into the inspection port and can be aimed over most of the tank interior. I siphon all the water into the bilge, then used the pressure blast to dislodge the sediment, mildew, etc. Siphon all that into the bilge and repeat again and again until there is mostly nothing left that doesn't look like water. The baffles make this a bit more challenging. The siphon hose has a stiff wire attached so I can aim it at the worst accumulations. The tank is HDPE and the crud has a tough time sticking to it so mostly it just comes off. While not 100%, the result is pretty clean and is easier than removing the tank.

I recently did a similar thing with mine. Here's a before and after pic...




When I get her back in the water I'll probably fill it up with water and bleach and let it slosh a bit and then a couple more times with water and baking soda. Hopefully that will get the nasties out.