[Public-List] V Berth Cubby - filters

[John Birch]

One of the big advantages to being at our marina is the number of scientists 
we have, particularly two who specialize in water quality issues. Both are 
award winners many times over. One is a recipient of an award from the 
International Joint Commission (IJC) recognizing his sizable contributions 
to Great Lakes water quality research.

Both these scientists do not favour using water filters in a boat tank. 
Their argument is that you actually concentrate the harmful bacteria in the 
filter, essentially creating a Petri dish. Silver halide filters only work 
for so long as does activated charcoal. Most boaters do not replace those 
filters properly.

They both make a practice of blowing emptying their tanks and ensuring the 
lines are clear, blowing them if necessary. If you need to shock a tank, do 
so, but drain it completely and just add water.

By not using various antifreeze, (non toxics) in the tank over the winter, 
the worst tastes caused by tank water will not exist. If you air dry the 
lines and use water only, after about 3 or 4 months any residue taste from 
propylene glycols absorbed into the plastic will disappear so you don't have 
to change your lines.

Personally, we do have a filter which I change each season, silver halide 
activated charcoal, and do add chlorine, but we use the water only after 
boiling for cooking, tooth brushing, hand washing and dish washing and 
toilet flushing and never drink directly from the tank unless cruising for 
extended times with really fresh water just taken aboard.

After all, isn't that why they invented beer, scotch and gin ; )


Best

John


----- Original Message ----- 
From: "dan walker" <dsailormon at yahoo.com>
To: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org>
Sent: Wednesday, April 07, 2010 10:12 AM
Subject: Re: [Public-List] V Berth Cubby


so with respect to chlorine. does it affect the fiberglass at all?

--- On Wed, 4/7/10, Don Campbell <dk.campbell at sympatico.ca> wrote:

> From: Don Campbell <dk.campbell at sympatico.ca>
> Subject: Re: [Public-List] V Berth Cubby
> To: "Alberg 30 Public List -- open to all" 
> <public-list at lists.alberg30.org>
> Date: Wednesday, April 7, 2010, 9:29 AM
>
>
> Kris Coward wrote:
> > Hi William,
> >
> > Changing the top and painting the inside would
> probably more than suffice
> > for me (and even that's somewhere near the bottom of
> my to-do list --
> > but then things have a habit of breaking and
> reorganizing to-do lists,
> > so...). Since my contemplation is usually provoked by
> the little white
> > bits in the water when the tank is low, or the
> weather's been heavy, I'm
> > going to assume that they're little pieces of aluminum
> salts all eaten
> > from the top of the tank.
> >
> The assumption that these are aluminum salts may not be
> justified. The flakes are much more likely to be
> calcium or magnesium carbonate salts from our hard water
> that have precipitated out because of changing water
> temperatures and similar reactions to any aluminum oxidation
> reactions but since calcium and magnesium are higher on the
> activity scale, they will react before aluminum will.
> Chlorine will only increase the number of flakes as you will
> find them similar to those with CLR. With these calcium
> compounds present, and chlorine, you get calcium
> chloride, a water soluble, deliquescent and
> efflorescent salt. This needs to be completely washed out of
> the tank system because it will keep releasing free
> chloride ions once dissolved in water (that it can attract
> from humidity in the air) which acts as a weak acid upon
> dissociation. The chlorine may then react with the aluminum
> and etch the surface if there is not enough calcium in the
> water to neutralize that reaction.
> The best thing to do is check the water
> in the tank for bacteria before you use chlorine and then
> choose your bactericide carefully. You may consider hydrogen
> peroxide to be better if you can get enough
> concentration from pharmacy available sources.
> Peroxide is a much sweeter chemical than chlorine.
> Municipal chlorine contents are about
> 6ppm. FYI. Dumping large quantities in without knowing
> concentration is not a good idea because chlorine or
> chloride is fairly toxic to all life, including you! I
> seem to recall from pesticide courses that sodium chloride
> is lethal for humans at 3500 ppm.
> Don
>
> > I only ever give the tank chlorine as a shock
> treatment if it's been
> > empty or standing for a few months (or something
> happens to cause me to
> > believe that it's become contaminated), so I've
> probably got some time
> > yet before the municipal chlorine starts causing
> leaks. Still, handy to
> > know nonetheless.
> >
> > Cheers,
> > Kris
> >
> > On Tue, Apr 06, 2010 at 07:46:09PM -0700, vmarmei
> wrote:
> >
> >> Hi Kris.....
> >> I did not install a new tank....I only
> changed/replaced the aluminum top for a new stainless steel
> top. I epoxied and painted the existing inside tank/hull
> wall....replaced the pipes and fittings to stainless steel,
> new hoses and put an 8 inch larger access deck plate for
> easy cleaning of the interior of the tank.
> >> I do add a little dab of Javex to the clean
> water......this chlorine over the years eats up the aluminum
> top and always contaminates the clean water....it also
> promoted water leaks from the bow.....that is the reason I
> did the work.
> >> The new water had a bad smell and taste for a few
> weeks...but after 2/3 changes of water over a month it
> became normal.....I rigged a 12 volt small portable weighted
> bilge pump,which I can now dump into the bottom of the tank
> and pump the whole tankful over board in a few minutes.
> >> This pump also helps to empty the tank before haul
> out......it is a nice conversation piece and makes me lots
> of A-30 friends who want to borrow it.
> >> William
> >>
> >>
> >> At 10:16 AM 06/04/2010, you wrote:
> >>
> >>
> >>> I've been contemplating dropping in a
> stainless tanky myself? Any
> >>> recommendations from your experience?
> >>>
> >>> Cheers,
> >>> Kris
> >>> 


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