Reliable thermometer?

[matthewscars]

Originally posted by defekt
Im interested in this.. where did you purchase yours?

drsfostersmith.com - why?

[matthewscars]

Originally posted by Slakker
Drops down to 79 at night according to the Coralife thermometer, so it's probably more realistically 77 or 76.

I suppose a swing from 76 to 85 could be enough to freak it out?

A daily 9 degree swing is not good. Knowing the accurate temperature is only half the battle.

Check out a beananimal article on heaters:

http://www.beananimal.com/articles/a...u-need-to-know!.aspx

So know that you know you have an accurate reading, you need to stablize the heat. Counting on your heaters internal thermometer is very dangerous.

I know you do not have money for the Ranco controller, but christmas is coming soon. I just dont want you losing all your stuff man.

good luck.

[jdieck]

Belive it or not I have found y comparisons to more precise thermometers that the Hagen $3.00 one is pretty accurate.
http://www.drsfostersmith.com/produc...21&pcatid=3921

Now if you really really have to have accuracy and precision the model 210-624-C in the link belowcould do it (0.1F divisions 24" long)
http://www.icllabs.com/astmnist.html

[Slakker]

Originally posted by matthewscars
I know you do not have money for the Ranco controller, but christmas is coming soon. I just dont want you losing all your stuff man.

good luck.

You're absolutely right, christmas IS coming and my parents have been bugging me for a list o' junk I want.

I checked the Coralife reading out of the display tank and it's telling me 80...both thermometers in the sump still read 84. I moved the glass one back up to see what the story is and it's reading about 83.

So maybe tonight has been uncharacteristically stable, but now a 2 degree swing doesn't seem so bad...

[brynkal]

So, worried now, the readout on a chiller is digital too, does that mean they aren't terribly accurate either, or are they somehow more accurate even though they're digital?

[jdieck]

Originally posted by brynkal
So, worried now, the readout on a chiller is digital too, does that mean they aren't terribly accurate either, or are they somehow more accurate even though they're digital?

The accuracy (digital or not) depends more on the linearity of the temperature probe and the ability to calibrate the instrument at different temperatures. In case of glass units depends on the manufacturer's testing and calibrating procedures and the reference they use (usually NIST standard).
Most cheaper units do not have any of those atributes so they could not really be trusted but having said that assuming the capturing device is linear withing the range of measurement of only a few degrees (most are) you can assume that the controller will be consistent. In other words one degree change in temperature will correspond to one degree change in the measure regardles if the reading corresponds to the exact temperature so you can change the setpoint until the temperature in the system is what you would like to have measuring with a more accurate reference and then set your span of control in the controller.
Say you set the the initial controller at 77 to 79 range and with that setting your tank is at 75 to 77 then you can increase the range of the chiller to 79 to 80 and due to it's linearity, the tank will be maintained at 77 to 79 regardless of the reading in the digital control of the chiller.
Of course for that you need access to another thermometer as a reference that is more accurate and basically this is what this thread is all about.

[kevin gu3]

Dunno if they've changed but last time I looked at cheapo floating thermometers there were about 6 on the rack at Wally World. All 6 read something different. Given that they only have a hash mark every 2 degrees thats a pretty wide range.

I siliconed sealed in indoor/outdoor thermometer's probe into an eyedropper and it hangs in my sump. No problems. I like the digit past the decimal point. No idea how accurate it is but the repeatability is very good. I think it was 10 bucks.

[Jandree22]

Originally posted by Santoki
this reminds me of one of the Rocky films where the Russian boxer trains with all these high tech equipment while Rocky trains by running around with a log on his back.
I guess with all the technology we have today, sometimes the old way is still better...

Love the analogy

[livingstone]

I can't believe anyone would expect (or report on) accuracy from a one dollar thermometer. Buy a laboratory grade glass thermometer for accuracy and to check your digital against. It could save a lot of lives in your aquarium.