which temperature is correct? Thermometers


New member
I have two thermometers. One is the coralife digital which is about two inches long. The other is a little bigger and is called the Big Digital Temp Alert by Pentair Aquatics. The problem is that the temperatures are not the same. The probes are located in the same area of the tank but the temps are almost 2 degrees off. The Coralife is higher than the other and I believe it is the one that is not correct (at least that's what I hope since it displays the higher temp). Has anyone had any experience with either of these two thermometers?


Premium Member
I bought a thermometer from Cole-Parmer that was certified to be within 1 deg F. It was about $50, but I think it was a good investment.


New member
I have the same problems with thermometers, I have tried all different kinds. So, I put six in and went with middle of the 3 that were closest in temperature to eachother and use that as my main thermometer.


I use the coralife's on my small freshwater systems. I have had a bad one before (Out of like 8 of them). However that said, working with both at work, I prefer the Coralife.


New member
Unfortunately it seems like amike5's suggestion is the safest. I do like the coralife but as I mentioned I believe it is the one that is off. I will have to purchase a couple others and use the one in the middle.

The reason I believe the coralife is off is because I unplugged the heater and the temp didn't go down much even though I know the heater was on. The temp of the other model did come down somewhat.


New member
if you have a cooking thermometer try that, and compare i had two digitals and one was 2 degrees too low, for about 5 monmths my tnaks was about 83-84, no bad effects too, with sps and clams.


New member
What is the optimum temperature range for a reef tank?

I'm cycling my first tank now and have been researching various forums trying to determine what the temp should be!

Village Idiot

New member
I borrowed a laboratory grade thermometer from work ($$$). It reads the same as my 4 inch long stick-on thermometer. I have a smaller 2 inch stick-on that reads about 2 degrees to high.

Travis L. Stevens

New member
Calibrate your thermometer. Take a glass of ice and water, stir it a little, and then put the thermometer in. Give it a moment to adjust and it should read 32ºF. If it doesn't, then it is off.