Severe Leaf Curl

Good day growers. Craziest thing happened to my seedlings today. I noticed a little leaf twist 5 days ago and had been concerned about RH at %30 in my basement so I slapped the dome back on for a quick fix. One day turned into 4 (with some intermittent fan exposure) and they were so happy in there but RH was getting up over %75. Today I had the dome off for 3 minutes and noticed some cupping starting. By the time I got my phone out they were curling up bad right in front of my eyes. I put the dome back on and in 10 mins they were back to normal. Since then I’ve slowly removed the dome again in stages with no ill effects. This run was for this purpose alone. They are my own bag seeds just testing out supplies, environment and some diff soil conditions.

What kind of light and how close? What kind of soil?

Lights are 15w Phillips daylight tubes at 6500k soil is happy frog untouched other than alternate kelp and coconut waterings. Humidity in the dome was closing in on %80. Humidity in the room was %28