%100 Accurate Thermometer and Hygrometer?

[PegasusRideR]

I have a Sauna Hygrometer(?) which was very expensive and showed no %100 humidity(most was %40, i'm using it for 2 years) but i live in a city where humidity often reaches to %100(usually in fall). And I have a thermometer which shows 26 celsius average(25 minimum, 27.5 maximum) but still my new sprouts' main branch is purple.

So, as you understood I'm looking for an analog hygrometer and an analog thermometer(celsius) which is accurate and will be accurate after years. I need equipments which I'll trust. And I need these equipments on e-bay and available for international shipping as I live very far away to the countries where pot is legal or anyhow supported (I even bought my lights from e-bay). Any help would be appriciated. Sorry for any grammar mistake as i value them in my language.

 

[Sgt.Stedenko]

If you have the funds, look for an Oakton Thermo/hygrometer. They get to the +/-2% range.
Nothing is 100% accurate.

 

[milehighmedical]

.

 

[geopolitical]

Dickson environmental monitors, but it'll need calibration at least once a year and it'll set you back around $200, $350 with local logging.

 

[PegasusRideR]

But just to get this straight... you think your stems are turning purple because of your humidity? I'm not sure if I've ever heard that conclusion before.

Stems get purple because of heat stress(low). When heat is lower than 23 celsius, stem turns purple especially in seedlings(This is the average degree for the plants i've known before). But I'll search for a high quality hygrometer intended for cigars. This is an interesting idea that I've never heard before. Thanks.

I'll search for other replies after I woke up tomorrow. Thanks for helping.

 

[foaf]

the most advanced hygrometers that can be used to regulate your setup are the ones used in fungus growing. This site isnt the cheapest but has a good selection as a starting point. http://www.fungi.com/tools/hygro.html

Ive got one, it has a built in 10 amp relay that can be used to trigger your dehumidifier or your humidifier, whichever way you need to take it. they are expensive. The most accurate hygrometer for just taking a reading would be a sling psychrometer. they are relatively cheap and are composed of two thermometers, one with a wet bulb and one with a dry bulb and a chart on the setup that helps you determine the accurate relative humidity.

My fancy hygrometer is the green thing

 

[growshopfrank]

I use one of these they are very accurate the only downside is that you need to top up the little res about once a week
http://cgi.ebay.com/PSYCHROMETER-WE...831?pt=LH_DefaultDomain_0&hash=item4cf2adc887

 

[PegasusRideR]

Thanks for the infos.

@Sgt.Stedenko: Sorry, I forgot to mention, I'm looking for analog products. And for thermometer it should be celsius. I couldn't be able to find analog products of Oakton. I only found an analog hygrometer with a digital thermometer.

@geopolitical: All of the Dicksons I could find were digital.

@foaf: That green one is 329$! I've changed my mind, I don't want it %100 accurate, I have to change the title

The most I can spend is 150$ for the two. But devices such as growshopfrank told would be perfect if an accurate hygro/psychrometer can be that cheap. By accurate, I meant 50 of those products on the shelf show the same. %2-3 miss would be no problem.

Psychrometer is a new thing to me. Never heard it before. I found this:

http://www.taftan.com/thermodynamics/HYGROMT.HTM

Screen hygrometer is Polythermal Professional Hygrometer in fungi and sling psychrometer is the one that is on the same page or the one growshopfrank gave right? So Psychrometers are more suitable for grow cabinets that we use because there is air moving continously? And you have to make the bulbs wet by putting it into water and waiting for some seconds for the results to show up? How does that work exactly?

I also wonder do we need humidity or relative humidity? I mean that when we read %45 is the best for flowering in grow guides is that relative or normal humidity?

I found one psychrometer which looks like the black one in fungi;

http://cgi.ebay.com/COMPACT-SLING-P...582?pt=LH_DefaultDomain_0&hash=item4ceb1b93de

I also found that sites related to fungus are somehow expensive. Can you give me a brand name and a model(ebay link would be awesome)?


@growshopfrank: You mean cleaning the sensor once a week?

 

[growshopfrank]

@growshopfrank: You mean cleaning the sensor once a week?[/QUOTE]

Not cleaning anything all that you have to do is keep a small (like 30ml) reservoir topped up with water. the thing works off a Principal of one thermometer is dry and the other is wet and you compare the difference with a supplied chart to calculate the humidity its easier than it sounds and is very accurate and reliable

 

[Baba Ku]

http://www.amazon.com/CALIBER-DIGITAL-HYGROMETER-CIGAR-HUMIDOR/dp/B001CZLO5W
There is an earlier report on these here and it was highly recommended.

 

[dunkydunk]

Good hygro/thermometers can be found in pet stores as well, in the reptile & terrarium section.

 

[Mountain]

Good hygro/thermometers can be found in pet stores as well, in the reptile & terrarium section.

Low priced hygrometers suck for accuracy. Getting an inexpensive, accurate thermometer is easy...not so with a hygrometer. I usually rely on my Johnson A419 commercial grade SPDT controller for temps. For humidity if you're even close for canna growing you're OK. No need for a high end hygrometer for canna IMO...just not worth it.

 

[PegasusRideR]

@growshopfrank: Sounds very easy. Thank you.

Seems most of the people only read the title here. I'm going to buy growshop's psychrometer and a cigar thermometer that milehighmedical suggested. I'll post here if there'll be a noticeable difference between them. For thermometer, I found one here. There were 21 on the shelf and 19 were showing same heat. Anyway, thanks for helping.

 

[potlatch]

Ah, reading comprehension--ANALOG meters.
Thanks for the info, growshopfrank!

I've got the Caliber III next to a Lacrosse and the displayed RH is rarely the same--worse, the difference is nonlinear.

 

[tr1ck_]

http://www.amazon.com/CALIBER-DIGITAL-HYGROMETER-CIGAR-HUMIDOR/dp/B001CZLO5W
There is an earlier report on these here and it was highly recommended.

^ +1

In this thread: https://www.icmag.com/ic/showthread.php?t=156237
Simon says he tested a bunch of hygrometers and the Caliber III was the most consistent, its also small enough to fit into a jar which is a plus

 

[Mountain]

^ +1

In this thread: https://www.icmag.com/ic/showthread.php?t=156237
Simon says he tested a bunch of hygrometers and the Caliber III was the most consistent, its also small enough to fit into a jar which is a plus

What I would try is buying at least 3 of these units then put them in the same location and see what the variance is. I tried that with another brand a few years back, can't remember which one, and the temps varied almost nothing yet the humidity was off quite a few % between the 3. Was an interesting experiment.

I saw that dude in that thread had 4 meters but was not interested in reading through the thread to see if he did an experiment like I did. Put them in the exact same enviro and then you'll know if they are the most consistent. I could not make out the readings on the 4 meters in that pic.

I read the specs on that meter and...

Accuracy +/- 1% humidity, +/-1 degree temperature

...while I can easily believe the +/- 1 degree for temp accuracy the +/- 1% for humidity is something I'm skeptical about. Not saying it's not true but I have my doubts. If that accurate, unit-to-unit, for that price then a killer deal for a hygrometer.

 

[simon]

I saw that dude in that thread had 4 meters...

I'm (err...) that dude in that thread, and I have about a dozen Calibers. One reads ~4% too low, another ~2% high, while the rest are +/-1% while in a sealed container. Reading ambient, there's a little more variance. For whatever reason, low priced hygrometers tend to be space-specific. I've had some that read ambient fairly accurately, but didn't do well inside a jar. I suspect that the hygrometers recommend by others would do better in a large space. FWIW, I use el-cheapos in the growrooms.

... but was not interested in reading through the thread to see if he did an experiment like I did. Put them in the exact same enviro and then you'll know if they are the most consistent.

<grin> I'm almost at a loss for words, as you seem to think that my IQ hasn't quite reached the triple digits. You can bet your ass that I tested not only the hygrometers, but the method itself over the course of many years. Out of sheer curiosity, what makes you think there's a single human alive who would not put all the pieces into the same environment, when confronted with a task requiring a given degree of accuracy and consistency, and gauge their readings?

I could not make out the readings on the 4 meters in that pic.

It wouldn't have mattered even if you could, as you'd have no idea how long each sat out, or was left in my hand, etc before the pic was shot.

Simon

 

[Mountain]

I'm (err...) that dude in that thread, and I have about a dozen Calibers. One reads ~4% too low, another ~2% high, while the rest are +/-1% while in a sealed container. Reading ambient, there's a little more variance.

That's pretty good for accuracy for that price. Never tested the meters I had in a closed jar and in an open space so interesting.

<grin> I'm almost at a loss for words, as you seem to think that my IQ hasn't quite reached the triple digits. You can bet your ass that I tested not only the hygrometers, but the method itself over the course of many years. Out of sheer curiosity, what makes you think there's a single human alive who would not put all the pieces into the same environment, when confronted with a task requiring a given degree of accuracy and consistency, and gauge their readings?

LOL!!! I never said or implied anything regarding your intelligence and did not question you...I just didn't know what you did in some regards. As for the second part you've got to be kidding me. You seem to think all in the human species have the ability to figure things like that out even when it seems straight forward.

It wouldn't have mattered even if you could, as you'd have no idea how long each sat out, or was left in my hand, etc before the pic was shot.

Yeah I'm familiar with how that works. Temps correct faster than humidity with meters and takes awhile for readings to stabilize. I mean if the readings were clear in the image and way off meter-to-meter I would have had some questions.

 

[potlatch]

I bought the ebay psychrometer (wet/dry bulb alcohol thermometer).
Sitting on a shelf in a bedroom:
Psychrometer = 58RH (69F dry - 60F wet; chart lookup)
LaCrosse "weather channel" (discontinued model) = 40RH
Caliber III = 36RH

Current conditions outside in my zip code (per weather underground) = 94RH, 40F

The readings among the three gages on the shelf have been stable for the last two or three days. I just bought another Caliber from ebay (cheaper than Amazon).

 

[PegasusRideR]

Thanks for all those infos. Psychrometer wet % dry... has arrived. I'm still trying to figure it out. The cigar hygrometer hasn't arrived yet;

http://cgi.ebay.com/Western-Instrum...339?pt=LH_DefaultDomain_0&hash=item3f048d7a13

Caliber 3 is digital and I don't trust digital equipments but after all those post I've decided to buy one. After all arrives, I'll post the differences between western insturments analog cigar hygrometer, psychrometer(no brand), my old harvia sauna hygrometer and Caliber 3.