sophie wrote:

could anyone with experience of the jäger aquarium heater enlighten me
as to whether "fully submersible" actually MEANS fully submersible? It
has a minimum water line and lots of lovely diagrams indicating how well
insulated the cable is, and an arrow pointing to a double sealing joint,
but no specific instructions as to a maximum level.
I'm assuming that I can in fact put the whole thing underwater (it's
been operating that way for a while now) but I've developed a sudden
paranoia about it. Can't find any definitive info on the net either, and
I thought I'd ask here before ringing the manufacturers...

many thanks for any help,

Every submersible heater has a minimum water line to prevent users from
overheating the coil and cracking the glass.

Where exactly would the manufacturer place the maximum water level line?
It would be an imaginary line set quite a few feet above the heater. ;-)

Fully submersible == fully submersible.

Nikki