I just got a 75W Jager heater to replace the no name one I had. The old heater was not stable and the thermostat was always 4-5 degrees F off. When I bought the Jager it said waterproof and submersible. On the heater and in the instructions it says not to submerge above the line (which is just under the temp dial). Can I fully submerge this heater or not? If not, I'm sending it back
