Can this be true?

[FLITZ]

80% 75% 61%...
Did I do that correctly? Can all three of my hygrometers be reading different humidity? OH and the one that reads correctly 75% is the exact same name brand/style as the one that reads 61%

Why do companies bother to manufacture a product that is off by so much. I mean its the entire purpose of a hygrometer..the ONLY purpose it has is to tell you a correct %...grr....I dont even want to get on a rant about thermometers..

I put some salt and water in a soda cap Just enough to get it really moist but not enough that any water would drip out of the cap if I turn the cap on its side.
Put this in a sandwich bag sealed with the hygrometers. The Hygrometers are Not the same distance away from the salt but i assume that doesn't matter. I did this 10-11 hours ago...did I wait too long?

with that said the 75% one and the 61% one that are the same kind... one has been sitting in my incubator... One is brand new.. the one that isn't new has been sitting in my incubator for a week ....no eggs...trying to get this stuff right before I kill off my first batch of eggs If they are off by that much...can i trust that they will always be off by that much or in a week will they be reading all over the place again (no screw to change them) OH GRRR.. I didn't mark the two that look the same so i have no idea which one is new and which one has been in my bator...

two are pet store $6.00. kind of cheap feeling...plastic
one is a pet store cheap one for reptiles has a thermometer that reads 2* colder than correct and Hygrometer combo around $11.50

 

[AlienChick]

All you have to do is keep note of how much of a percentage the hygrometer is "off" from 75% after you calibrated it.

So the one you have that reads 61% will have to have 14% added to its reading each time.

Hygrometers are a pain, but at least it gives you a general idea of what the humidity is.

I do not keep my humidity at one particular level during the first 18 days anyway.
I just add water whenever the humidity drops significantly (more than 10%) -usually every 2-3 days.

Good luck with your hatch!!

 

[Ridgerunner]

Different thermometers and hygrometers are made to read within different degrees of accuracy. This has nothing to do with reading the actual temperature or humidity, just how close they repeat the readings. For example, some thermometers are made to an accuracy of 1 or 2 degrees. Some are made to read an accuracy of 0.1 degrees. This means that if you put a thermometer in a known temperature and take it out, then put it back the repeatability of the readings will be within that range. It does not mean the thermometer will read the correct temperature. Due to manufacuring tolerances, they may actually read something totally different.

The next time you are in a store that sells thermometers for measuring outside temperatures, which normally have a repeatability of 1 to 2 degrees, check them out. I've seen as much as 9 degrees F difference with the same cheap thermometers on the same shelf.

You can get very accurate thermometers with very good repeatability and that actually measure the correct temperature. These are made to very tight manufaacturing tolerances and are calibrated. They are not usually very cheap. If you want to trust a thermometer or a hygrometer you have to calibrate it yourself.

With all that said, I'm thinking about a recent post where someone was looking in garage sales for a can opener made before 1980 so they could get one that does not strip the gears after just a few uses. And I'm thinking about a very expensive food processor, a Paul Prudhomme model supposedly strong enough to make bread dough, that is a piece of junk because a plastic part broke on the bowl when I was washing it, I cannot find another bowl on Amazon, and the company does not make them any more. Just because I understand mass producing stuff and that even expensive stuff is often useless, I don't necessarily like it. I have expressed my views to the company and rated that product on-line.

The best I can suggest is to calibrate your instruments so you at least have an idea what is going on. And I do wish you luck.

Somewhat like Alienchick, I use my hygrometer to tell me when to add water. I really don't worry that much about actual humidity. But the temperature, I like to know.

 

[FLITZ]

Yeah thats what im going to do. Add 14 to one .. take away 5 from the other..and hope they stay like that and not start reading differantlly in a week.
Maybe I'll pick up another and change them out from time to time.