Heater thermostat vs Thermometer...

"Marcus Fox" wrote in
message ...
I have my heater set to 79/26 (F/C) but my stick-on LCD thermometer is
showing 82/28. The heater is by Visitherm, it's 100W fully submersible.
It
can be set in increments of 0.5C. It has been used for about one month.
Which should I trust, the thermostat of the heater, or the thermometer?

Marcus

From my experience, neither. I use a digital thermometer to check my
aquarium thermometers against, and then use them and ignore my heater
thermometer completely. Most thermometers & heaters work ok, but have an
offset (couple degrees too high or low). Once you know the offset, you
can do your calculation. I think the LCD type are also susceptible to
greater inaccuracy on very hot days, so you might have a hot summer day
offset, as well as the usual offset. Fortunately (with all these offsets
;~), stability is usually more important than the relative number
(provided you avoid the extremes).

NetMax

If your thermostat is set to 79 but the weather is warm, the thermometer will
obviously register a higher temperature. i think that I would trust the
thermometer if I had a choice.

Marcus Fox wrote:

I have my heater set to 79/26 (F/C) but my stick-on LCD thermometer is
showing 82/28. The heater is by Visitherm, it's 100W fully submersible. It
can be set in increments of 0.5C. It has been used for about one month.
Which should I trust, the thermostat of the heater, or the thermometer?

Marcus

I had a thermometer that read low and I almost cooked my fish trying to
raise the temp to 80F. Pick up a new one and test it with the old one.
Chances are good that it is the old one gone bad.

Vicki