Stupid thermometers.. What do you trust??

barclayrl

barclayrl

Premium Member
I have had my reef setup for about 2 years now... I got a few of those nice digital thermometers from hellolights, and put them each in different tanks. I later drained the other tank and put both thermometers side by side and found they were over 4 deg F. different..... What the heck!! So one read 79.6 the other 83.9

This got me interested; my RK2 was calibrated a few years back with an Old school Mercury style thermometer. It read 80.2.

So then I put a new thermometer in the tank (One of them that has small lead bb's in the bottom of it. With the red dye in it, It read 75.5...... )This is really out of wack... What do you all trust for accurate temps???

What should i do at this point...

Here once again we have $1000's invested in our tanks.. This all rides on these <$5 pieces of equipment..

Ryan
 
I have the same frustration. I'm more concerned about actual swings then actual temp as long as I'm within a degree or two.

I think I'm going to invest in a calibrated medical or lab grade thermometer that claims accuracy within a 0.2degrees or better accuracy. I wont keep it in the tank, but just use it to check the accuracy of the probes or stick-on. It seems most of the aquarium thermometers are +/-2.0 degrees and some don’t even publish it.
 
Just to think....an awesome reef tank getting taken down by a faulty thermometer!

I have two stickies and a semi-cheap electronic on my tank. Thankfully, they are all pretty close. I used to have one comparable to the one Jeff linked but it met it's maker and needs to be replaced.
 
Maddening isn't it? I have this same issue right now. Chiller reads 83.5, Hello Lights free digital reads 86, stick on one reads 79, floating one reads 80. Which do I trust? I know the chiller temp probe has issues, the Hello Lights one...well there is a reason it is free, the sticky one on the side was never meant to be accurate. I trust the floating one as I have several of them and they are all close.
 
I got a calibrated thermometer and use it to periodically check all the rest. Guaranteed accurate to within 0.1 degrees.
 
<a href=showthread.php?s=&postid=12426068#post12426068 target=_blank>Originally posted</a> by scottdwh
What about infrared thermometers? Are those accurate with water?
Click to expand...

I started to go that route but the ones I looked at were +/- 2 degrees.
 
Use an old style bubble thermometer as a fail safe IMO. I keep one floating in my sump. I find that the inexpensive coralife digital thermometers are dead on with my Ranco temp controllers. Some controllers and electronic thermometers are affected greatly by halide lighting....they basically get fried. I had a bad experience with ProHeat controllers.
 
i use the in tank thermometers and what i set my heater at and the intank is only off by a degree
 
this is not the best method, but try to put your probe into a glass filled to the top with ice and topped off with water. this should give you a temperature close to freezing. At least you can separate the really bad thermometers from the good ones. oregon scientific was best at this method.
 
All my electronic thermometers are slowly starting to die off one by one. I just use my hanna pH/orp meter everyonce in a while. Some of the digitals were up to 2 degrees off when they died.

I would look at your corals and how they appear to be doing. Happy corals mean your doing something right.

Honestly, I dont really think about the temp anymore.
 
<a href=showthread.php?s=&postid=12426275#post12426275 target=_blank>Originally posted</a> by cbrownfish
Use an old style bubble thermometer as a fail safe IMO. I keep one floating in my sump. I find that the inexpensive coralife digital thermometers are dead on with my Ranco temp controllers. Some controllers and electronic thermometers are affected greatly by halide lighting....they basically get fried. I had a bad experience with ProHeat controllers.
Click to expand...

Well put.

I know that using a digital _fill_in_the_blank_ has a fun, techy feel to it, but as far as thermometers go, digital just puts another step in the process of reading physical change of a material to determine the temperature.

Meanwhile, those liquid crystal stick-on-the-tank feel blatantly susceptible to error based on the fact that the only things they are going off of to tell you your water's temperature are the temperature of the glass and the temperature of the air.

For these reasons, I find that the float-in-the-tank thermometers are absolutely the most accurate if manufactured correctly and they are all I will ever use, unless I buy a digital thermometer for "entertainment" purposes.
 
I would say that you should really rely on the analog thermometre (old school glass therm) more than you should digital. The problem is that while although digital thermometres are very precise, they aren't always more accurate. There are a lot of things that can go wrong in the digital thermometres that analogs just don't have. The only thing that can go wrong with the analog is that the glass is broken somewhere, wheras in digital the probe could be bad, or the electronics could be bad. In most laboratory settings I've seen, analog is always trusted over digital as the failsafe.
 
I just got an American Marine Pinpoint wireless one to replace my stick on the tank ones I have been using. So far I like it a lot. I left one of the stick ons on the side of the tank near the bottom as sorta a check to make sure it and the digital were around the same temp. My digital reads 78.1 with the mh lights off and the stick on is green at 78 so I am assuming they are both working.
 
I have a mercury calibrating thermometer that I purchased from Mikelite.com. It only goes from 66-80 but that was ok. I keep my tank at ~79. I took it to work to check against our NST certified thermometers and it was dead on at 72 and 78 - good enough for me. It was only 24 bucks and it is almost 11.5 inches long, good size and easy to read. Recommended highly.

http://shop.mikelite.com/product.sc?categoryId=-1&productId=31
 
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