Eggs getting mouldy

I am having BIG trouble with my incubator this year, first it wasn't maintaining the set temperature (replaced Honeywell T-stat with herpstat - worked) and now 3 out of 5 eggs start looking mouldy after only three weeks in the incubator.

What can I do?
Lower the humidity?

Robb

i believe that is a sign of dead eggs. :(

Your humidity should be high. there should be some condensation build up.

What kind of incubator are you using?

It's a DIY incubator, basically and insulated wooden box with flexwatt between the bottom layers.
I use sterililte tubs in it that I cover with a glass screen.

Temps are 31.3 - 31.5°C (88,34 - 88,88°F), humidity is at 90%.

Substrate is Vermiculite.


Robb

Robb, there are many unanswered questions. However, my first would be, Did you candle the eggs? And, if so, were there any veins in those eggs?