Accurate thermometer

[Gingerlove05]

Yep thats a glass thermometer
They’re the only type I have granted they are normally just floating around the tanks but that’s because i need some new suction cups

[Martinspuddle]

Can somebody post a link to the thermometers they use (and trust) please? My water is feeling questionably cool and my cheap digital thermometer doesn't fill me with confidence, going to move it to the other side of the tank further away from my filter outlet in the meantime to see what it records.

For general use I have stick on thermometers on my aquariums which I just use as a daily glance but just as a guide. Aquarium thermometers have never been very accurate, indeed if you take ten glass aquarium thermometers in the same tank there will be quite a variation in readings of plus or minus 5 degrees in most cases I found. Do also remember there can also be a small difference in temperature between the bottom and top of the water column especially in large deep aquariums, so I always leave my stick on thermometers at the bottom and at the opposite end to the heater.

For waterchanges I still use an old glass aquarium alcohol thermometer (Circa 1970's) but for a more accurate reading I have a medical mercury thermometer which the old glass thermometer does nearly match. I started using a mercury thermometer with my old reef aquariums, especially with marine invertebrates which are susceptible to changes in temperature.

Any FSA approved (food standard agency) thermometers or medical, laboratory thermometers digital and mercury thermometers should be pretty much spot on.

[Sixo]

Variations of 5 degrees is quite a difference!

How do you use the medical one do you just dip it in or have you got it fixed to the tank in some way?

I know GL I've yet to come across a suction cup that doesn't give up the ghost.

[Staffylover]

Hi, I have a stick on glass type for just basic checks but mine is flat with a plastic surround as I find this much easier to read plus it's magnetic so don't get the annoying suction cup issue, if I want to double check I use this one on link below it's been great has a metal probe that clicks back into plastic body, when you open it out it switches on, I got it for using in outside tub but it's been a great back up for all the tanks

https://smile.amazon.co.uk/gp/product/B ... e=UTF8&psc

[Martinspuddle]

How do you use the medical one do you just dip it in or have you got it fixed to the tank in some way?

I don't keep the mercury thermometer in the aquarium, I just use it for testing.

[black ghost]

When people say a glass one do they mean one of these?
I think a 2nd thermometer to compare readings would put my mind at ease

They’re incredibly inaccurate, simply because the cards are glued inside on the cheap as it were, and there’s no consistency as to the card’s precise location. If you must buy one of those, get it from a physical shop so that you can look at all of them. If you look at ten, five might show the same temp, and the rest will vary either side of that. Get one of the five(?)... but that still doesn’t guarantee that it’s right.

I use a simple glass thermometer bought from a chemist (Boots), similar to these (just google oral thermometer).... They’re designed for human oral use so they’re very accurate.

https://www.cromwell.co.uk/shop/measuri ... xdEALw_wcB

https://www.amazon.co.uk/Geratherm-clas ... 3840&psc=1

I used it to calibrate all my crappy aquarium ones. They all have +2, or -1, etc written on them now (and they were all originally bought as “one of the five”).

[Sixo]

Think that's exactly what I'm needing for peace of mind thanks for that.

[Stephen]

How do you use the medical one do you just dip it in or have you got it fixed to the tank in some way?

I don't keep the mercury thermometer in the aquarium, I just use it for testing.

Me too

I was watching a YouTube video yesterday about setting up a breeding tank for my Flash (L204) plecos.
I found it interesting as the guy was using one of those temperature guns (similar to those being used by nurses when you turn up for an appointment).
I said to myself, what a good idea that would work.
Checking on-line those temperature guns can be bought for as little as £9.00, many were around £12.00 and some were £20.00+

All the best

[Jon_D]

Variations of 5 degrees is quite a difference!

How do you use the medical one do you just dip it in or have you got it fixed to the tank in some way?

I know GL I've yet to come across a suction cup that doesn't give up the ghost.

Stick in in the bottom of the tank.... Sorry, I'll get my coat now....

[FishyMcFishFace]

I use my elbow never fails.

You are never going to get a constant level temperatue throughout a tank with heaters being the way they are. as the thermostat and heater are in the same location, the hotter water is always going to be closer to the unite and colder the further away it is.