Accurate, reliable thermometer?

[mcsassy]

I just bought another JBJ Digi-temp thermometer to replace the one that the rubber suction cup on got chewed threw over time and it's reading at pretty high temperatures. Mind you, I haven't had one in the tank for a couple weeks, so I don't know what to make of it, but my temperature never read over 82 before...usually would hover between 81 and 82. The new one said 83.7 when I put it in the tank today and hasn't dropped past 83.3 even with night fall and lights out. Is there a way to test its accuracy other than putting it in colder water or whatever?

I'm checking out some of the ones on this page with probes...can anybody recommend a top notch one to me? Doesn't have to be from that site.

http://www.techinstrument.com/acatalog/Panel___Wall_Mount_Thermometers.html

Edit: Seems like the only one on that site for aquarium use is the A150Q

[mcsassy]

I also forgot to mention my heater is set on 78. It's an aqueon 200 watt heater in a 72 gallon tank.

I have the Coralife 265 PC light hood as well...it puts out heat, but so much as to need a chiller I would say.

Something has got to be the culprit here...I just want to know the REAL temperature of the tank. Would it read higher if placed in the sump as well since the heater is in there? My thermometer is in the top right corner of the tank right now against the wall.

[Almondsaz]

ON my DT I use the temp probe from my ACIII and it is accurate because I regulate it with a temp gun (total nerd I know). I have used http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3744+3841&pcatid=3841 on my little 12 gallon nano and my previous 75 gallon and it has been very accurate. I also have purchased the little $5.99 temp on DFS and it was as accurate as well.

[mike_nikki]

If you can find a Old Mercury/alcohol floating Thermometer... they were very accurate(cant beat a mercury/alcohol thermometer) you can match it to the digi one and and calculate the difference. i did it and my coralife digi was off by 2 degrees. so when i look at my digi now and it reads 77 degrees and now know its really 79

[mcsassy]

So if I stick any alcohol thermometer in there, that's pretty much guaranteed to be the most accurate reading and the standard to abide by and compare to?

[mcsassy]

I put the thermometer in my brand new fridge, which is set at 37 degrees. It dropped to 38.8, then I checked again later and it was at 42...unless my refrigerator is fluctuating, then there is something the matter with this thermometer.

Edit: Now it's at 47.8...umm ya. Something is wrong with it and not my fridge haha.

[mike_nikki]

A mercury thermometer is actually the best IF you can actually find one they stopped making them along time ago. but yeah, your digi is freaking out if its doing that unless the fridge is doing that by opening and closing the door alot

[mcsassy]

A mercury thermometer is actually the best IF you can actually find one they stopped making them along time ago. but yeah, your digi is freaking out if its doing that unless the fridge is doing that by opening and closing the door alot

I took it back to my LFS...they just gave me another one no questions asked. I was testing out my new one in the car on the way home and it was responding very well to the air conditioner...problem is that it was stuck onto the rear view mirror and as my friend was parking, it fell off and broke! I took the battery out and put it back in a few times and it turned on again...funny thing...I left it in his car! Will report back when I get it back and have more stats...oy.

[mcsassy]

Okay, the new one says my tank is 85.1...that's even more than the other one said! I'm going to go get one of those alcohol based ones from petsmart and see what that one says and report back.

[Ace25]

LOL. I never rely on thermometers for temp. I have never found one close to accurate. I use a controller like Almondsaz to control my 2 heaters. I also use a cheap coralife digi thermometer, a digital "meat" thermometer, and an infrared temp gun to get readings on my tank and get an average about once a month just to make sure the controller temp probe is good. My controller is usually the most accurate and matches the temp readout on my chiller to within .1 degrees.

Reefkeeper Lite is only $99 and will control your heater perfect.

[mcsassy]

Ace, it seems like I have much to learn then about all this techy stuff...I didn't even know what you just mentioned exists. I bought one of those Rainbow Lifeguard thermometers today with the alarm and stuff on it...I haven't opened it yet though. What's this infrared gun and how does a controller control your heater? Doesn't the heater itself have a thermostat? What's the best heater you recommend as well? I have an aqueon, but I don't know if it's the heater's thermostat that's messed up or what. Teach me, please!

Edit: I just read about the RKL and now I have some questions. What is " RKM-PC4 (total of 4 outlets) ", does it eliminate the need of a thermometer with the temperature probe and how does it control the lights and wave maker? Do you use it on the MP40W? Probably not, because it has it's own night mode. How many lights does it control up to? It eliminates the need for timers? How does it control the heater?

[mcsassy]

Okay, I think I figured it all out now.

The entry level RKL comes with an RKM...which is a surge protector basically that plugs into the head unit. The heater can be plugged into the surge protector along with the lights and then the head unit has timers that can be programmed to tell the lights when to turn on and off and then it has a temperature probe that acts as a thermometer and also when you plug the heater into the RKM unit, the head unit will tell the heater when to turn on and off and ultimately override the heater's own thermostat, correct?

[Ace25]

Yup, last post was 100% correct. I have the Reefkeeper2 on mine, does Ph and also has 8 outlets instead of 4, but for $99 for the basic one it is a good deal, although I really like the pH probe addon so I can see the pH anytime of day. I have my heaters set to just a little over the cut off temp on the controller and have my controller turn both my heaters on when the temp drops below 79.7 and turns off at 79.9. I also have my MH light and 2 T5s on it as well, and another good thing about a controller is it will automatically turn your lights OFF at a given high temp reading. I have mine set for 84, if the water gets hits 84 the MH light turns off, 84.5 the T5s turn off. My temp should never read that high, but if it does then I know my chiller is malfunctioning and I need to look into it. Without the controller I may miss something like that for a day which could be real bad news for corals.

Tempgun.com (http://www.tempgun.com/order.html#pe2) to see an IR temp reader.

[mcsassy]

Definitely cool! I'm going to return the rainbow lifeguard and get a reefkeeper lite. So, even if the thermostat on the heater may be faulty, the RKL will override it and make it irrelevant?

[Ace25]

Yup, the thermostat in the heaters being exposed to saltwater really make them "iffy" at best, especially over time. The RKL overrides the heaters thermostat because it turns the power socket off/on at a given temperature instead of relying on the heaters internal thermostat to do the on/off function. I set my heater to turn on around 80-81 on the dial on the heater itself so when the RK kicks on the heater will turn on. If you set the heater too low it wont turn on even if the RK gives it power. Seems like a "Well.. Duh!" thing to say, just pointing it out so no one makes a mistake. :D

[mcsassy]

Yup, the thermostat in the heaters being exposed to saltwater really make them "iffy" at best, especially over time. The RKL overrides the heaters thermostat because it turns the power socket off/on at a given temperature instead of relying on the heaters internal thermostat to do the on/off function. I set my heater to turn on around 80-81 on the dial on the heater itself so when the RK kicks on the heater will turn on. If you set the heater too low it wont turn on even if the RK gives it power. Seems like a "Well.. Duh!" thing to say, just pointing it out so no one makes a mistake. :D

So, you set the heater higher than you actually want it to work at. That's what I was thinking of doing when I get mine, but thanks for clarifying and saving another question! I was actually thinking of getting a new heater because I don't trust mine's thermostat any longer, but I'm not going to get a new one anymore with the RKL! Thanks for telling me about it too because I would have never known about it otherwise. I guess I will just get it through my LFS because I'm returning the thermometer and it would probably be just as much to have it shipped to me as getting it there and paying tax...CA...just went up to 9.75% grrrrrr...

[Ace25]

Use the promo code "NOCALTAX" at checkout on MarineDepot and you don't have to pay CA taxes. ;)

[mcsassy]

Use the promo code "NOCALTAX" at checkout on MarineDepot and you don't have to pay CA taxes. ;)

Oh thanks! Do they do free shipping on orders of a certain price or more? If I can get free shipping too, I will definitely get it from them. Otherwise I can just get it on ebay or from my LFS.

[Ace25]

$175+ is free shipping, so you need $75 more with the RKL.

[mcsassy]

Ace, their affiliate website...PetStore.com has free shipping on their items. It's basically the same exact site, but just another name...they have a link to it on marinedepot.com

Anyways...I put in the promotion code "nocaltax" on petstore.com and it didn't work haha. It worked on marinedepot.com...so its either pay tax or pay shipping. I bought it on ebay from the petstore.com website and they charged me both tax and shipping! I immediately e-mailed them and told them to waive one because it caught me out of left field.

[barbarossa4122]

I just bought 2 MARINA stainless steel thermometers ($ 6.00 both) and I am happy with them. They show the same temp as my digital (MagLife) and my other cheap glass therm.