Seedlings, Advice/ Help Me!

i bought a jiffy greenhouse with a heated mat, put some water in the inside for the peat pellets to absorb, planted seeds in every one which would have been 72 seeds in total, about half sprouted to my suprise in 3 days, i have them under four 48'' 32 watt floro's, two warm and two cool white about 3'' above the seedlings and have them running 24/7 but the seedlings are ranging in size from anywhere from 1'' to 3'' and my thermostat inside reads about 30 i've had them growing like this for about a week and a half now, a few of the seeds wernt doing jack so i got rid of them, i have 34 seddlings as of today, should i change the lights to 18/6? is the tempature inside the dome to hot for seedlings?, is the lighting ok?, is the size of the seedling's normal for a week and a half?, thanks

oh and i shut the heat pad off because i figured that the roots may have been getting to hot and i've been leaving the dome on most of the time but i usualy take it off a few times a day to air out and pellets are not drowned with water or dry ever.