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Discussion Starter · #1 ·
Ok, here is my situation. I've been using one of those stick-on-the-glass thermometers for the longest time (YEARS). Now I knew these weren't the most accurate gauges for temp, but I felt they would give a good indication as to where my temp reading was at. We've been having some cold weather here in San Diego as of late (no snow, but wish I had more logs for the fire - lol) and the readings on my stick-on were heading south alot (lower readings than -76). I thought maybe my heater is acting up (stealth visi-therm - no light indicator to let you know it's on-off). So of course once I crank the heater up some, the stick-on would read 78 to 80!! So then I would lower the heater reading and then eventually find the stick-on reading 70 to 72!! I was like ok, something is defnitely wrong here!! (the temp set on the heater was not even close to matching the reading on the stick-on thermometer)

Some may be asking, did you stick your hand in the water to feel it's temp?? Yes and that is why I became really concerned because at the almost 80 reading(the stick-on therm), the water didn't feel that warm. Now I was really worried. So I went out to go buy a digitall thermometer. It would have been cheaper to buy in online, but I didn't have the time. I picked up the Coralife Digital Thermometer and brought it home, along with another otto and some free pond snails for my dwarf puffers. :tongue: Anyways, as soon as I put the dig. thermometer in my tank it gave me a reading of 72, but the stick-on was green at 76 (heater set at ~73). I would like my tank to be around 75, no higher. I move the temp gauge on my heater to almost the 75 degree mark. Well as time went by, I checked the readings: stick-on was approaching 80 and the dig thermometer was reading a little over 74 degrees. But I relied on that darn stick-on so much that I lowered my heater again to around 72-73 mark. Nightime came and I was getting a reading around 71 on my dig therm, but my stick-on read 74-75.

I, of course was getting sick of this, so today I decided to check out the accuarcy of my dig thermometer. I took out my dig thermometer from my tank. I took 2 big glasses and filled them up with water: one cold and the other hot. I used a kitchen dig thermometer and my aquarium thermometer and tested each water sample. First the cold: kitchen therm read 71 so did my aquarium therm. Then for the hot water: kitchen therm was 104 and so was my aquarium therm. This was good enough for me to determine that my digital thermometer was the accurate temp reading gadget! :proud: (Note: I should have done this testing first before putting in it in my tank. It would have saved me and my aquatic inhabitants grief.)

I placed my digital thermometer back in the tank and set my heater to almost 75. So hopefully now I can get the right temp in my tank to around 74-75 degrees. :) I shudder to think how long my poor inhabitants had to endure the not-so-good temps!! Nightime they were living in below 70 degrees of water! YIKES!! :eek5:

Now I'm trying to gauge how well my heater works. :icon_roll

Moral of this story...............stick-on thermometers SUCK!!! :angryfire Time to scrape off that evil graffiti from my tank!!!
 

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Yeah, they do suck. I also don't like those little floating glass type thermometers. I later switched over to a digital LCD temps (Big Temp alerts) and I have never gone back since then. I use them for all my main tanks and also the smaller Time and Temp thermometers on my other tanks.
 

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The bad news is: just because it's digital, it can still be off.

I have a Big Digital Temp Alert that I've had for years. I also have one of the small $7 Coralife digitals. The $7 one seems to be pretty close. The Big Digital actually reads low, nearly 2 degrees.

I've often wondered if it wouldn't pay to buy a DECENT glass thermometer. Used to be photo suppy places had pretty accurate ones available so I could verify the digital one every now and then.
 

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Scrape those stick-on thermometers off your glass... they are not precise enough, and room temperature affects them as much as water temp.

I used to be a big supporter of digital thermometers, but like Steve, I found that some are not very precise either. Electrical interference can mess them up, battery can go low and effect the reading, especially for the cheaper ones.

I finally found one thermometer that is working extremely well:


Aquarium and Pond products. SeaMe.com/int Internetshop for Aquarium and Pondproducts

Unfortunately, I don't know if something like that is available over here, and in Fahrenheit...
Basically it is the same as those floating glass thermometers, but it is about half as thick, and the scale about twice as large. I can see the exact temp from a couple of feet away. Extremely precise too.

Next time I go to Europe I'll get one for each of my tanks.
 

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For about $20 (USD), I wouldn't really expect lab precision digital thermometer. I do use several types of digital thermometers and notice about +- 2 degrees difference between them, which is not a problem. Also the placement of the probes will also make a difference. The reason I like them is I can actually see the temp instead of guessing if it the temp is at either 72 or 74.

The nice thing about the Big Temp alert is it will sound an alert if the temp goes above or below +- 5 degrees (adjustable) of my desired temp.
 

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Discussion Starter · #6 ·
Yeah, that color guessing game is moronic! Greenish on one temp, bluish on the adjacent temp. It was just pathetic! Room temp was definitely playing around with my stick-on thermometer. Just way off the mark.

At least the digital thermometer is alot more closer to the correct temp reading of my tank water. I like the one I have because I can turn it off and on; a real battery saver. Chaging the battery every 6 months, I think, should be more than adequate. I know when I set up my CRS tank, I will definitely get the "Alert" dig thermometer. That is a nice feature.

It would be nice to have a seperate thermometer, that gives a very accurate reading, so that I could double check the dig thermometer in my tank. Guess I'll have to keep my eyes out for one. :)
 

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Discussion Starter · #7 ·
I was just checking out that site that is selling the JBL glass thermometer. I see that they are in Holland! I've always wanted to go there!!! :) Can I use this as a good excuse to go? LOL Hmmmmmmmmmm.... they have free shipping to all countries if you spend 75 Euros or more. I think I would rather go visit their store. hehehe
 

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Scrape those stick-on thermometers off your glass... they are not precise enough, and room temperature affects them as much as water temp.

I used to be a big supporter of digital thermometers, but like Steve, I found that some are not very precise either. Electrical interference can mess them up, battery can go low and effect the reading, especially for the cheaper ones.

I finally found one thermometer that is working extremely well:


Aquarium and Pond products. SeaMe.com/int Internetshop for Aquarium and Pondproducts

Unfortunately, I don't know if something like that is available over here, and in Fahrenheit...
Basically it is the same as those floating glass thermometers, but it is about half as thick, and the scale about twice as large. I can see the exact temp from a couple of feet away. Extremely precise too.

Next time I go to Europe I'll get one for each of my tanks.

I also bought this under the brand name of SERA. They are VERY accurate and have a large scale which allows for easy reading. All my other stuff is now in the bin.

chris
 

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I've got three of the coralife digital thermometers. 1 of them is spot on all the time, 1 reads around a degree high, and the other reads around a degree low. The two that are a little off are always consistenly off, so I have a good idea of what the temp is anyway.
 

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Yep, that's the thermometer that I bought in order to "Calibrate" my Coralife Thermometers. Coralifes are only accurate to +/-1C (1.8F). Out of 10 I only have 1 that is right on.

I calibrated each thermometer and made my notes. Opened MS Word and typed it onto 2"x4" self-adhesive mailing labels. Cut them out and stuck the appropriate one on each thermometer. Now I can tell at a glance what the actual temps are. Temps are very important to my project, so $24 shipped was a baragin for a Thermometer that's accurate to 0.25F!

I'll post a pick later--short on time now.....

HTH
 

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Discussion Starter · #14 ·
Cool! Now if I could only find a good, accurate heater! -argh- My Stealth Visi-therm is crap. I set it to 75 and my tank is pushing close to 80 now. I try setting it just a little below 75, to like 73-74 ish and my tank drops to 70 degrees! Looks like I'm going to have to send this back to the manufacturer and get a new one. But I'll have to find a replacement first. This is crap!! :angryfire
 

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It sure is, I had Hydor 50 W that would not go below 77*F even if I set it at 66*F:mad: I just had enough and took it back to the store and later got a great 50W from a trade with a member of this forum. Keep trying, there is one for you out there somewhere:smile:
 

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I have the Coralife mini digital. It reads about 1.28 lower than the monitor for the heater controler in the 2126 Eheim. I only use it for reference as the Eheim controller is in the cabinet. The only problem I have encountered is that the "on/off" button doesn't work. It's on all the time. I haven't even bothered to open it up to look at it.

Tommy
 

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"For about $20 (USD), I wouldn't really expect lab precision digital thermometer."

Check around, you'll be surprised what you can find.

Accurate to +/- 0.25 deg F
Paterson 12" Color Thermometer

Google "used lab equipment". You'll find places that sell used and sometimes reasonably priced new stuff.
It's still not a digital thermometer.
 

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I have the Coralife mini digital. It reads about 1.28 lower than the monitor for the heater controler in the 2126 Eheim. I only use it for reference as the Eheim controller is in the cabinet. The only problem I have encountered is that the "on/off" button doesn't work. It's on all the time. I haven't even bothered to open it up to look at it.

Tommy
You need to hold it down for 5 seconds. :)

As for measuring temperature, I use two Coralife digital's but only as a rough measurement. I don't see why you need it accurate down to the 0.1, but if I want an accurate measure I use my Milwaukee pH/temp meter.
 
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