I am making a cylindrical nickel plating tank as I find that the bucket I
usually use often isn't deep enough - currently need to plate some 27"
shafts. So I've made up a 30" length of 160 mm underground drain with a stop
end at the lower end. Shape is ideal as I can drop a tank bubbler in the
bottom for agitation and the entire length of the shaft will be agitated.
However although I've been using fish tank heaters in a plastic bucket, and
they've survived the occasional 'total immersion', in this tank they will be
well under the surface. It occurs to me that they might not stand up to this
treatment - any opinions?

(I have a fall back plan to slip a suitable diameter plastic tube over the
cable and top 1" of the 'test tube' that they are built in, secured with a
plastic clip but I'd like to avoid it as the plastic tube will be relatively
inflexible and tend to knock over the vessel)

These are the heaters I'm using:


http://tinyurl.com/fish-tank-heater


Andrew