Humidity too low?!
 

Hi, my Hermann tortoise is about to lay eggs so I've made my own incubator using a poly box with a heat mat and bricks etc. The temperature is at 31/32c. I'm struggling to get the humidity up past 60%. Occasionally it gets to 63% but them drops again. I've got 3 massive sponges in the incubator and there is condensation on the walls! I've done the salt calibration test on both my hydrometers so I know they are fine. I don't know what else to try :( please help, these are my first eggs and I really want them to hatch.
Dom

I am not sure Dom, I was advised to put more water in as it was more surface area that was needed.... Someone is bound to have some ideas x x xhugs x x x

Do you have the sponges in containers?
I generally have an old plastic (deep) chocolate box in my incubator. With a sponge and filled to the top with water. I have never in over 34yrs worried about any more humidity, and have never measured it for incubating tortoise eggs. I just keep the container topped up all the time.
I have also incubated tortoise eggs in an airing cupboard with out any humidity at all in there (before I new about humidity).

I had a home made incubater made from a poly box and solved the problem by lining it with a plastic bin liner, I had fairly large holes in the lid and with the liner managed to get the humidity a lot higher. By cover/uncovering the holes with sticky tape I was able to adjust the humidity to what I wanted, I think that polystyrene absorbs some of the moisture in the air and by lining it you make the box waterproof. If you think most incubaters are made of plastic it makes sense anyway have a go you'll have to take everything out and put back in but it does work.

I don't think polystyrene absorbs water as it is used to transport fish. I think some incubators are made of it anyway

The easiest solution is to concentrate on the environment in the container for the eggs rather than trying to balance the the incubator. If you use a plastic tub, leave the lid on with a few hole punched in. Watch for condensation on the inside of the lid. You can either have it at a slight angle so drops roll tothe edge or place a sheet of kitchen roll betwen the eggs and the lid.

Water bowls in the incubation will help prevent moisture escaping the egg tub.

I breed aquatic turtles where humidity is crucial and this works fine for them. I use vermiculite with the same weight of water; 100 grams (weight not mililitres) per 100 grams of vermiculite.

I incubate Hermanns at around 75-80% humidity.

maybe poly doesn't absorb water but I do know that when you add a plastic liner you can increase the humidity easily where as without its near impossible so to me the poly does something.

Hi, I have 3 sponges in there at the moment. I'll try the bin liner and the lids on the tubs when I get home and see if it helps. Fingers crossed.

Let us know how it goes Dom..... X x x. Hugs x x x

I have to change the water in the plastic tub everyday with hot water, this brings the humidty up to 75-80% then the next day it goes down to around 65% x