On Oct 2, 12:40 pm, druid wrote:
Hi,

I've always seen plastic watertanks, but the boat I'm buying has an old
aluminum one (I think it's alum: it's metal, and not SS). Is there any
advantage to alum over plastic or vice-versa?

Hi

I worked in a university research oyster hatchery as a bio lab aid. I
was the summer help. But the people who worked there were all PhD
types. I scrubbed glass wear. One of the things the lab did was test
hatchery materials and water supply materials for toxicity. We used
oyster larvae for the indicator in the bio assays. Basically,
fertilize the gametes in water with a test material. Observe the
development over time. Different materials kill/deform baby oysters at
different rates.

What I learned in two summers. Oysters are very sensitive creatures.
Just about anything will kill em. A material must be really inert
(safe) for an oyster to like it. For example, 316 L. Copper, on the
other hand, is death to an oyster. Do a little research regarding
effects of Aluminum on our brain. So goes with many plastics.

Ya Ya Ya yada yada yada in know now all the republicans o, and our one
libertarian will pipe in and say you'd have to eat a pound a day for
50 years to have any deleterious effect. So go for it.................

I had two 1979 Al tanks on my boat when I bought it. After yanking
both out and tearing one open I found pitting every where. Looked like
the pox. I eye estimate that 30-40% of all inside tank surfaces were
pitted and 100% surface was rough. Then I wondered where all that
material went????????????

Now I have two tanks on board. One 40 gallon and one 20 gallon. Both
are made of 316 L.

Forget plastic and forget Al...................
Some things ya just cant filter out using charcoal and paper.

Besides, its a boat. Why even conseder anything but the best.

Live long and prosper,
Bob