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View Full Version : most accurate way to measure temperature


woogy
10/20/2008, 04:14 PM
I have a TDS meter that measures temp as well as a mag float in the tank that has a LCD temp on the inside of the tank. One says 78 and the other 81. Which is more accurate or is there a more accurate way?

tmcgaughey
10/20/2008, 04:18 PM
I'd go buy a cheap digital aqarium themometer and see what it says ($10-20)

Who knows with those things?!?

woogy
10/20/2008, 04:23 PM
I have one of those on the 29gallon and it reads about a 3 degree difference as well compared to the temp on the TDS meter

tmcgaughey
10/20/2008, 04:28 PM
Hmmm.. when you measure with the TDS meter. Do you take the water out of the tank? or do you measure in the same spot?

Like, when I test my liquids. I put them in a container and test from there. My thoughts would be it could cool down but 3 degrees is a good chunk. I still think another thermomter would give you a better idea of which one was lying and which one was telling the truth. Even if you borrow one from a friend. Do the buy it - use it - take it back and it wouldn't cost ya anything?

woogy
10/20/2008, 04:30 PM
no in the tank and tried different spots

tmcgaughey
10/20/2008, 04:39 PM
Hard to tell. Easiest and best way to check those things (outside of a lab) is with another thermometer. I don't know if you TDS meter has to be wet to check temp but you could take both of them out. Let them dry and put them next to your thermostat in the house (assuming it's digital) and see which one is closest.

atvdave
10/20/2008, 04:41 PM
To the best of my knowledge, you should not use a TDS meter in salt water. Or at least thats what I have been told.

I don't know if it will affect the temp reading's or not.

MileHighFish
10/20/2008, 06:18 PM
i was told to get a cup of icy water let set till nice a cold then test.. it should be very close to 34.. a friends dad is a health inspector and he does this when testing fridges.. just a thought

crvz
10/20/2008, 06:26 PM
<a href=showthread.php?s=&postid=13585936#post13585936 target=_blank>Originally posted</a> by g stone
i was told to get a cup of icy water let set till nice a cold then test.. it should be very close to 34.. a friends dad is a health inspector and he does this when testing fridges.. just a thought

That's a good thought, should give you some reliability in the meter you're using, but some of them don't measure a large range very well. I have a couple of newer temp probes and I just use them to check each other, but I usually don't worry about a couple degrees difference.