Nute burn: where to go from here? (kush, HPS, aerogarden)

Hi There,

I've got a couple of Hindu Kush clones growing in an aerogaren under 150w HPS, and it looks like I'm getting some burn. I'm using Foxfarm and followed their hydro schedule. I'd just put 3 tsp Grow Big, 1 Tbl Big Bloom, and 1/4 tsp Open Sesame 5 days ago, but have switched to pH 6.5 adjusted water (no nutes) after noticing the burn. I plan to switch to 12/12 today to start flowering, and wonder when I should add new nutes and at what strength. Also, this is my first use of the 150w HPS (switched due to crappy yields from CFLs), and wonder if the light is at the right distance from my plants. Could the light be too close and causing the burn? It's about 10 inches from the top of the plants.

Thanks!

FoxFarms nutes are more powerful then they say.

I dont know where to lead you now, but I do know FoxFarm tells you to add more then you're supposed to.