Mold on my Seedlings PLEASE Help!

Hey everyone names GanjaGus and I am working with a small indoor tent CFL grow. I have some seeds that I accumulated personally and some ordered and I used the paper towel method for all. I had great success with 7-8 seeds sprouting roots.
After I planted them into coco rooters inside the dome on a seedling heat mat. After 5 days I lost 4 of the seedlings to mold, now this is the second time this has happened and I do not know what I am doing wrong.

What I am using
-42watt CFL
- Heat Mat
- Dome
- PH water 6.0-6.3 ( for coco)
- 77-83 degrees
- 80%-91% Humidity
- Light cycle 18-6 on a timer.
- CO2 Pad every 3 days
And as a side note I uncover the babies at least once a day to let a little fresh air in to them. andI had opened the vent on day 3. Please anyone with advice would help and save me a lot of time and aggravation.

i don't know the ways that your using. what i do is pop them in a damp paper towel, get a 16oz to 24oz styrofoam, cup pock a few holes in the bottom. fill with (if able if not then what i can find) organic soil. once the germed seed has a root i place it about a inch in the soil and water, then set to the side till it breaks the surface. as soon as it breaks i put it in the light with air movement around it. i also try to keep my humidity below 50%. the summer is when the humidity is highest, in the winter while running a heater it goes down to 28% and lower so i'm sometimes trying to add. i don't like high humidity as you get mold and bud rot. so try it a different way and see how it goes. good luck.

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- 80%-91% Humidity

Do you think this might be a problem? A camel would grow mold at this humidity. Forget covering them, keep a breeze blowing nearby. Pretend it is the plains of Afghanastan, try to duplicate something more like that. Buy a book.