Very noobish question related to temperature

[Realpedro]

I haven't been using heaters in any of my tanks. My thinking was that my house has a very stable temperature of 75-76F (about 24.5 C) and all my fish fit those parameters so I didn't need to worry about it. I assumed the water in the tanks was about 76F. But as I've slowly been trying to improve my skills, I bought a thermometer and checked the temperature of each of my tanks. They all read 82F! Now I'm worried.

How can an unheated tank get so much hotter than the environment around it? I'm using LED lighting, so I assumed that wouldn't add too much heat. Is it possible my thermometer is inaccurate or can fish tanks get much warmer than the air around them? I feel like I am probably missing something very simple.

 

[Fishmanic]

What type of thermometer are you using?

 

[Ch4rlie]

As Fishmanic asks, what kind of thermometer are you using?
This could possibly have an effect on accurate temperatures.

But if it is accurate at 82F then simple answer is that it’s too warm for your livestock if you have fish other than rams or betta.

Most fish can tolerate slightly warmer water but only for very short terms.

The effect of warmer waters is that increases their metabolism and thus stresses their bodies and this in turn shortens their lifespan, by how much I am not sure but warmer temps definitely has an impact on livestock no matter which way you look at it.

Easiest way to lower temp is to do a water change with slightly lower temperature but is not economical if your tank reaches 82F daily and having to do this every single day.

Is your tank situated in a warm area when sun shines in the room for a long time or shines on the tank or is the tank near radiator / fire if you regularly have these on?

 

[seangee]

How well is your tank ventilated?
While it is true that LED lights are cool the units actually produce a surprising amount of heat. That is why LED car / motorcycle headlights usually include a fan and / or heatsink.

I have 4 tanks with LED lights. On average the temp in these tanks inreases by 2C (4F) while the lights are on. So if (as an example) your tank temp increases by 4F in the 8 hours your lights are on, but only drops 3F in the next 16 hours then the temp in your tank will gradually build up. If the thermometer is accurate this would explain the difference.

 

[Realpedro]

As Fishmanic asks, what kind of thermometer are you using?
This could possibly have an effect on accurate temperatures.

But if it is accurate at 82F then simple answer is that it’s too warm for your livestock if you have fish other than rams or betta.

Most fish can tolerate slightly warmer water but only for very short terms.

The effect of warmer waters is that increases their metabolism and thus stresses their bodies and this in turn shortens their lifespan, by how much I am not sure but warmer temps definitely has an impact on livestock no matter which way you look at it.

Easiest way to lower temp is to do a water change with slightly lower temperature but is not economical if your tank reaches 82F daily and having to do this every single day.

Is your tank situated in a warm area when sun shines in the room for a long time or shines on the tank or is the tank near radiator / fire if you regularly have these on?

Not getting sunshine. There is no external heat source with the obvious exception of the LED lighting.

Here's the kind of thermometer I'm using. My kids ran off with the packaging, but it's this guy right here:

 

[Ch4rlie]

That’s a very similar digital thermometer that I actually use on my tank, only mine is black.

Hmm, could be the lighting unit that outputting a lot of heat and that’s effecting the tank temperature, not unusual and sometime you do see fans next to light unit in effort to combat heat output from light unit.

But I am not not an expert on light unit at all whatsoever so can’t really comment on that side of things but I do know some light do give out a lot of heat and some light units come with fans In order to counter the heat.

Not too sure how effective fan light units are but as I say, usually it’s direct sunlight or radiators being on that is the usual culprits for raised tank water temps but lights, that’s a whole other ballgame for me am afraid.

 

[utahfish]

If your tank has a lid then all the heat that goes into the tank even minimal amount from led lights gets trapped just like it would in an enclosed terrarium increasing temperature. Tanks with open tops will have more air flow, increased water circulation will also dissipate heat.

 

[Metalhead88]

That exact thermometer almost killed all of my fish.

It was reading 78 or 79 and no matter how high I turned up my heater, the thermometer would not show over 80 (which at the time I wanted since it was for a tank with rams) The water felt so warm and after double checking it with a glass thermometer, the temp was over 90F......no wonder electrical bill was so high after setting the tank up.

I'd suggest double checking it with a different thermometer.... it doesn't really add up.

 

[Realpedro]

That exact thermometer almost killed all of my fish.

It was reading 78 or 79 and no matter how high I turned up my heater, the thermometer would not show over 80 (which at the time I wanted since it was for a tank with rams) The water felt so warm and after double checking it with a glass thermometer, the temp was over 90F......no wonder electrical bill was so high after setting the tank up.

I'd suggest double checking it with a different thermometer.... it doesn't really add up.

Yeah, I just bought a simple mercury thermometer this morning and remeasured the temp in two tanks. One was 74 F and the other was 76.

Happily, it seems like my fish are fine, and I just had a scare with a bad thermometer.

 

[Metalhead88]

Yeah, I just bought a simple mercury thermometer this morning and remeasured the temp in two tanks. One was 74 F and the other was 76.

Happily, it seems like my fish are fine, and I just had a scare with a bad thermometer.

Glad to hear.

Those things should even be sold. Being off by almost 10 degrees is insane.

 

[Ch4rlie]

Yeah, I just bought a simple mercury thermometer this morning and remeasured the temp in two tanks. One was 74 F and the other was 76.

Happily, it seems like my fish are fine, and I just had a scare with a bad thermometer.

Well, that’s the best outcome we could have hoped for, thank goodness!

Sometimes these cheap digital thermometers are just simply not worth it and always worth double checking readings just to be sure.

I have a digital TDS meter that also has a temperature option, not the cheapest equipment tbh but I knew it would be far more accurate than most cheap thermometers and used this to check temps if I was suspicious but as it happens I was lucky with any thermometer I bought as most were pretty accurate anyway but always worth double checking just to have that peace of mind.

 

[seangee]

Just FWIW I find those thermometers fairly good when they work. I tend to buy them in packs of 4 and test them all together. Any that show a difference of more than 0.1C to the rest I just throw out. I also tend to throw out and replace when the battery goes, typically 12-18 months. They are so cheap this is no problem.

Here is an example of what I was saying about the impact of LEDs. These 2 thermometers have identical readings. The top one has the probe in the water and the bottom 1 is measuring the air. Lights have been off for around 9 hours and the difference was 2 degrees when I went to bed last night. The room was also a full degree warmer than it is now.