Date:         Sun, 8 Aug 2004 17:27:04 -0700
Reply-To:     Nancy Eilers-Hughes <keithahughes@QWEST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Nancy Eilers-Hughes <keithahughes@QWEST.NET>
Subject:      remove mold from water tank-Westy
Content-Type: text/plain; charset=us-ascii; format=flowed

Jeff,

Can I use bleach to clean out a little funk in my drinking water tank
on my
Westfalia? She's got a little stinky muck, mold, algae--I don't know
which--in
there.

Bleach is fairly ineffective when you have a biofilm in place (the
black gunk you see). You need to mechanically clean (aka scrub-brush)
the tank, and *replace* all of the pvc tubing - this is crucial,as
the mold will actually grow into the tubing, and will provide a
'reservoir' for growing the next generation of biofilm.

1. How much bleach to water should I use? Or is there a better product?

3%-5% hydrogen peroxide is better, but much more expensive. There are
many other disinfectants, but none that are safe (without rather
heroic methods) to use in potable water systems. Well...to be
accurate, you can also use either Bromine or Iodine, neither of which
however are as effective as chlorine.

To go the chlorine route (after getting rid of the visible
slime/gunk) you need about a 500ppm solution for optimal performance,
especially to kill mold spores. This equates to about 13.5 oz. per
gallon of Clorox (5.25% sodium hypochlorite by volume). It helps to
add a couple of ounces of vinegar, per gallon, to acidify the solution.

2. How long does the concoction need to sit in the tank?

You need at least a 15 minute contact time, but a little longer is
always better.

3. Is it advisable to scrub the tank through the opening on the top?

Yep. And rinse the crud out thoroughly before adding the chlorine
solution. Free chlorine will be sequestered by any organic materials
in the system, so the cleaner you start, the better off you are.

4. Should I, or could I run the concoction trough the drinking water
pump and
faucet to make sure there's no offending growth in those channels without
damaging the pump or faucet?

You should be able to, although the solution will be hard on the
metals and elastomers. Especially since they're probably pretty old now.

Keith Hughes
'86 Westy Tiico
Phx, AZ.