On Wednesday, 7 September 2016 15:08:19 UTC+1, Andrew Mawson wrote:
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

I'd have thought they;d be alright as the are designed to be submurged mine was almost always under the water.

I;d be very worried by a heater that looked as though adjusting teh temperature with wet hands looked dangerous as it's difficult to adjust these things without getting yuor hand went and even your arm while adjusting such things.

I wouldn;t worry if buying from a shop but buying these cheap ones from ebay I might be more careful.

Regarding not letting them sink to the bottom I don;t think it's the PSI, it's that if it was in left on the gravel over time it could create a hot spot on teh glass as normally the heater relies on water passing over it to cool the outer glass which can get pretty hot if not underwater. So if it's resting on teh bottom it could cause problems as the glass wouldn;t call as expected, again with a cheap ebay item I'd be more worried.