i'm sure my hygrometer has gone wacky, but i'm still concerned

[chkinut]

ok guys, i guess i'm posting about this just to get reassurance that i'm doing the right thing not to trust my hygrometer. i just did a hatch not to long ago and the chicks are 1 week old. everything was fine with my humidity and temp. humidity 38-40% and at lockdown 58-60%. anyway, on my new batch of eggs, on day 5 today, it has been reading high (50% or higher) so i was told it was from my bator being full to the max and the eggs were loosing moisture. sounds good and makes sense. but just now when i went to turn them i noticed the bator was completely dry. i hadn't added water since i added the eggs. dry bator, but still reading 55%. so i took the whole hygrometer out and kept it out for awhile and the humidity did NOT go down. so i think it's messed up or needs a new battery. i've been hatching for......well, this is my 3rd year. i've always had to add water. i always hatch at the same time of year too. i don't believe that where i live is so high in humidity. so....i added water to the center well like i do for all my hatches. and now my hygrometer says its 77% in there. but i don't trust it. humidity in my area couldn't have changed so drastically in 1 week i wouldn't think.
i guess i'm looking for reassurance that i did the right thing.

 

[chkinut]

and now it's reading 51%

 

[sherylreno]

Have you calibrated your hygrometer before? I take a cup and place salt in the cup. Sprinkle enough water to moisten the salt but do not add too much, the salt needs to be like wet sand. Place the cup with the salt in a large enough plastic bag to seal it. Place the cup and the hygrometer inside the plastic bag. Zip the bag shut and do not touch it for 8 hours. Once 8 hours has passed then look at the %, it should read 75%. If it does not say 75% then there is a small screw in the back. Turn the screw until the hygrometer reads 75%.

 

[chkinut]

wow! thanks! i had heard of people calibrating them and it all seemed very confusing to me but this way sounds pretty straight forward. will i work for a digital one?

 

[Egghead_Jr]

I had two digitals, one you could calibrate and other you couldn't. Usually a turn knob and push button thing not a screw. I put a label on the one couldn't be adjusted- +4%. You know, label it how far it's off from 75% and how you'll remember add or subtract to your readings. Mine was 4% low so wrote +4 so I'd add that. However you'll remember is the key.

For the "cup" holding damp salt just use the cap of a large mouth soda or water bottle.