On 2010-04-06 07:59:11 -0400, "John Smith" said:

Probably already know the answer to this, but thought I'd check here just in
case.

About 7 or 8 years ago I got a Visitherm 100W tank heater and was running it
without incident for a few years. Sometime after, this tank was switched to
holding coldwater species and instead of removing the heater from the tank,
I just left it unplugged.

Now, I'm not sure if there's an optical illusion or something, and although
I have fairly good eyesight, it looks to me like there is water in there at
the bottom. I did test the heater by switching it on across an RCD and it
behaved as normal. I didn't see the water touch the heating element though,
and I wasn't going to be handling it whilst in these circumstances.

Can there really be water in there, I thought these things were 100%
waterproof, even after all this time?

Nothing is going to be 100% waterproof forever. At some point it will
leak or the heating element will fail. If you have water in therem get
rid of it before it makes contact with the heating element and shorts
out your house, or electrocutes you fish.

Andy