Quote:
Originally Posted by Bob1201
Alan, I might add that you should get about 5 years with --- easy enough to jump over the side after 3 years, and check how it's going. The Oxy is now available on line, in my day I had a mate who was a chemist ---- Who,
may I say, said it wouldn't work 
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Funny you should mention that. Interesting paper here:
http://www.researchgate.net/profile/...7ff74943a4.pdf
"The preparation of antifouling paints using tetracycline
powder results in an unstable product that is
rapidly leached by seawater. Within a few days much of
the tetracycline will have been removed and concentrations
at a boat's surface will be extremely low. Toxicity
tests on marine bacteria and marine algae suggest
concentrations in the mg 1-1 range would be necessary
to provide antifouling activity on
boats. These concentrations
are unlikely to occur with this paint. The
small amount of tetracycline that is released from a
painted hull will be rendered biologically inactive
through complexing with calcium and magnesium in
seawater, producing little risk to non-target organisms.
Tetracycline cannot be considered persistent in the
aquatic
environment as epimerization and photolysis
will together produce a half life in seawater of about
130 h.
Oysters do not appear to take up tetracycline at a
significant rate at concentrations several orders of
magnitude higher than might possibly result from this
paint. Tetracycline found in
oyster tissue does not
reflect any magnification over
water concentrations in
this
experiment. It is likely that tetracycline taken up by
the
oyster is transferred to shell, and not stored in the
flesh. From observations with salmon bone, it is
probable that the tetracycline bound to shell will be
stable and not remobilize into tissue at a later date.
Regulating authorities can therefore be assured that
the use of tetracycline in antifouling paints does not
pose an environmental threat to marine ecosystems.
However, it is unlikely that such paints would be
effective antifoulants."
I have friends who, in the past, swore by putting tetracycline (easily available at vetrerinary supply stores) in their
bottom paint, but none of them currently do. Maybe next time I paint I will do one hull with and one without.