Whats up with my ak47 seedlings?

I have 9 under a 600w hps, and 2 under a cfl hood, the cfl ones are fine but the ones under the hps loov deformed a little on some the leaves ar curling up a little, i think it could be heat stress what do you guys think?

looks like heat stress.

looks like very low humidity and the HPS to close to the seedlings... 600w at very beginning should be 3-4feet away...

Someone told me i wanted it about 18 inch away??

For 600W without a cooltube 20-24inches would usually be fine, but for seedlings I recomend to put them 4 feet away, and during about 3 weeks slowly reduce the distance to a little less than 2 feet and keep it there unless your reflector and your ventilation permit you to go even closer... Seedlings more than older veging Plants need high air humidity, close to hot bullbs the humidity usually is very low, you should also hang a wet t-shirt or something else into you closet to rise the humidity, as more humidity you can get than better