Hey there topcat!

I've been growing in a tent for quite some time now and I can relate to your issues. From what I can tell - there's a few suggestions I can give:

1. When your plants are as small/young as they are, you might want to consider starting with a few floro lights close to your seedling instead of the big 600 just yet. I use power-bars with those plug-in light sockets and the warm/cool bulbs to start my plants off. The 600w light is drying out your peat-cups way to fast from the heat. Turn off the 600 for now and go in close with some small CFL lights to start.

2. Since you're in a tent, you want to get some 'negative' air-pressure going so that your tent walls actually get 'sucked in' from your fan exhausting the tent - then be sure to have passive intake holes at the bottom of the tent to allow fresh air to get sucking automatically... that will bring your temps down quite a lot.

Question - how big is your tent?

I hope that helps - please let me know if you need more help! =)
Dayzt1 Reviewed by Dayzt1 on . lighting my tent with a 600w dual spectrum - Help i'm a 1st timer bought a tent kit that came with a 600 w (sunmaster dual spectrum) however even with my 5" fan and filter I'm running temps around 100f. should i buy a lower watt Metal halide bulb for the veg stage? then switch at flowering with the addition of another inlet fan to keep temps lower during the end stages? I've got the light approx 1 metre above my seedlings (running 18/6), they are stretching up (currently 2 - 3inches) and the 2nd set of leaves are showing through. Would appreciate Rating: 5