How Responsive Are Digital Thermometers?

[martin_jones]

I bought a tank and it came with a 2nd hand digital thermometer.

I am beginning to wonder if it is working correctly.

How responsive should they be?

Yesterday, my 260L aquarium was running at 26.5 degrees.

I did a 100L water change with rainwater from outside.

The thermometer was then reporting that the temperature was 25.5 degrees.

I would have imagined that the cold water from outside would have triggered a bigger increase in the temperature than it did.

(This morning, my rummynose tetras weren't looking so red, and my cardinals seemed to be lacking their red stripe too, which I am putting down to the temp change - will test water params tonight).

Any thoughts?

Martin

 

[mr.dark-saint]

If you have "people" thermometer you can guage that along side the digital to see the difference. The old Mercury ones seems (to me) to be more accurate than the current alcohol numbers. The digi - therm I got is a old (at least ten years old) from a Radio Shack one of the 10/15 dollar specials. I'd say it's accurate enough. Mine has two meters (outdoor with a probe and ambient on the unit) from just sitting on the shelf it will tell me what both are and they are rarely off by .2 degrees. If the ambient reads 77.5 then the probed may read 77.3 since it dangles closer to the ground (colder air sets at the floor level).

100 Liter is what 25 gallons (or there abouts?)? And your tank is 260L is 65 Gallons? That's more than a third of the tank. So what was the temp of the fill water? Was it close to 25 degrees? If it was then there would've been not much of movement on the meter. You have to get some sort of a base line to work off from.

As for the faded colour I'd chalk it up to either too much water change (drop or rise in pH) or the Digi-Therm is not reading correctly. Or something came in contact with the rain water. Diesel exahust, soot, or whatever that may have washed off and in to the barrel (or a reaction of water with your collection container).