Digital Aquatics Reefkeeper Temperature Probe Replacement - DIY?

Jason777 · Jan 16, 2019

andrewprime1 said:
This might be a stupid question... But how are you guys hooking these probes up to your RK? My temp probe finally died after ears of faithful service and I am looking for a solution, fast! I bought the probes that Jason777 is testing and I am thinking I am just gonna have to splice in the male connector from my old DA probe. It looks like an RJ11 terminal, can I just buy some phone cable ends from home depot on crimp the in?

You can use the RJ12 connector from your bad Itemp. The DA probe only has 2 wires and you can just cut the RJ12 off the probe and splice it to the wires on the thermistor. Alternatively, you could get a new RJ12 connector or get Molex parts and switch from the Itemp port to the Temp port, if you have one. There is some more info in this thread:
https://www.reef2reef.com/threads/alternatives-to-digital-aquatics-probes-and-parts.439573/

Jason777 · Aug 7, 2019

Just an update on the plastic coated thermistors. Both of my tanks have been running on them with no problem for over 6 months now. One is running on a lite and one on an elite.

n2585722 · Aug 7, 2019

Thanks for the update. I will have to get one and try it.

Jason777 · Aug 13, 2019

n2585722 said:
Thanks for the update. I will have to get one and try it.

@n2585722 did you continue to test the stainless steel ones? Did they work OK after you sealed them?

n2585722 · Aug 14, 2019

Jason777 said:
@n2585722 did you continue to test the stainless steel ones? Did they work OK after you sealed them?

I have only tried 2. The second one is drifting and I need to replace it. That makes 2 failures. I just have not got around to replacing it yet. I do still have some DA temp sensors so I have not been in a hurry.

Hitman · Aug 18, 2019

Out of curiosity has anyone tried to use the Apex temp probe?

n2585722 · Aug 18, 2019

If Apex uses the same thermistor it would work. There are several different types of sensors out there. Even with thermistors there are lots of varients.

Hitman · Aug 18, 2019

I have a old spare apex temp prob that I just may have to try out.

n2585722 · Aug 18, 2019

You can check the probe with a multimeter if you have one. Get the resistance of the probe in a glass of ice water and then in your tank water if you know what the temp is and compare them to the chart for the DA probe. I think I posted the chart in a thread on R2R. I will see if I can find it.

n2585722 · Aug 20, 2019

I added one of the sensors in a shell from an old pH probe a while back. I just hooked it up to my SLX and it is in the tank. Time will tell but so far it is very stable.

Jason777 · Nov 2, 2019

Here's another update for anybody stumbling onto this thread looking for a replacement probe. Amazon quit carrying the plastic covered thermistor with the JST connector that I have been using for over a year with no problem. While I still have another spare I thought I should search out a replacement before I need to use it. Amazon has a 5 pack of Ucontro aquarium temperature probes so I ordered them to try. Initial installation looks good and I'm running graphing on one to make sure there is no significant drift. Once it has run for a while and I can compare graph results I'll post back and let everybody know if they work.

Jason777 · Nov 10, 2019

Results: After a week it looks like the Ucontro themistors should do OK. It tracks closely with my other one but there is a small difference, I suspect this would not be a problem since most of us are working in a very small temperature range. Today was the first chance I had to let the house warm up and let the tank temperature increase a little. I keep my tank within a very narrow range totaling 1.2°, set at 77° on the low with 78° for the high with a 0.1° hysteresis on each end. Today the temp raised 0.9° and there was a 0.1°-0.2° difference between the two thermistors. This would be a large error if you were working over a large temperature change so take that into account for your setup. The thermistor controlling the tank was going from 76.9°-77.0° during the past week while cycling the heater and the new one showed 77.0° with an occasional change to 77.1°. Today the old one went to 77.9° and the new showed 77.8°. Since the new one started a fraction higher and ended a fraction lower it does show a difference. Of course, I'm not using any type of calibrated control so who knows which probe is actually most accurate. One note I would make is that regardless of the probe, even a DA probe, I would calibrate it in the RK at the temperature you intend to keep the tank.

If anybody would like to see the graphs you can PM me. My previously noted problem graphing from the SLX module would most likely create more confusion so I don't intend to post them. I'll continue to monitor the difference between the probes on the RK to check for major drift and life of the probe but will discontinue the graphing. If anybody has any further questions or suggestions feel free to let me know.

JordanM · Dec 4, 2019

I have one of these temp probes for sale. Not sure what they are worth anymore. PM me any offers if your interested.

Fábio Cruz · Dec 22, 2020

JordanM said:
I have one of these temp probes for sale. Not sure what they are worth anymore. PM me any offers if your interested.

Hi, Do you still have the temp probe? Mine is gone and tried diferents sensors without sucess...

eulalio flores · Jan 24, 2021

Jason777 said:
The temperature probes for the reefkeepers are getting difficult to find so I'm interested in finding a working replacement. n2585722 has done some investigation with a 10k NTC thermistor and I have tried one but find it to be too sensitive for use. The digital aquatics probe gives a nice square wave on the graph while the thermistor is very unsteady. Maybe this is the wrong thermistor or maybe there is some stabilizing circuitry built into the DA probe? My electronics knowledge is limited so I'm hoping someone can figure out how to do this before our probes quit working.

Are you still looking for a probe