Neptune APEX TEMP PROBE FAIL?

special-ops-s2k · Sep 5, 2020

So today I experienced what I think is a Neptune APEX TEMP probe failure? I have had my tank running for about a year and up until this point the probe and Apex have performed flawlessly. However today I was notified that my tank temp had risen from the 79 I normally maintain to 84+ in a period of about 2hrs. It started rising at .1-.4 degrees per 10min interval and continued to rise at that rate until it reached 84+ and sort of floated there. My tank had already taken all measures programed in to lower the temp. Both cooling fans were running, the heaters were off, it had shutdown my UV sterilizers and the T5 lighting... When I came home to this I immediately thought the temp was really that high but did check it with my lab grade thermometer and was relieved to find it was only 77.3 !!!

I recalibrated the apex probe and I'm keeping an eye on it. Is it the probe that went bad? Something with the apex head unit? I'm really disappointed that this failed in this way and am thankful it didn't happen when I was out of town as I would have been panicked thinking it was correct.

What are everyone's thoughts on this event? I'll be buying a new probe and probably a secondary to back it up. But what does the community think is the cause of this?

SuncrestReef · Sep 5, 2020

A friend of mine experienced a similar jump in temperature recently. We discovered that the temperature probe was exposed to air because her ATO wasn't working and the water level had dropped in the chamber holding the temperature probe. Before you assume the probe is failing, confirm it is properly submerged in water.

special-ops-s2k · Sep 5, 2020

SuncrestReef said:
A friend of mine experienced a similar jump in temperature recently. We discovered that the temperature probe was exposed to air because her ATO wasn't working and the water level had dropped in the chamber holding the temperature probe. Before you assume the probe is failing, confirm it is properly submerged in water.

Thanks for the input and that is absolutely a possibility. I did double check that before posting and recalibrating my probe. The probe lives in a series of baffles and as such is always completely submerged. I did check my ATO levels and made sure the sensor hadn't been moved somehow... Unfortunately it was submerged and unmoved. I really can't figure out why the probe would just "all of the sudden" drift so far out of calibration and in such a short period of time!