Hm, that's not TERRIBLE for temps, but if your lights are 26" from the plants, at 1000w each, you 're likely to burn them just with the lights too close. And remember a rooted clone needs to get used to HID light. Its little root system might not be ready for that high rate of transpiration yet. I'd get the lights to 4 feet and leave them there for a while. I never would put a HPS1000 closer than 3 feet to my plants when I run one, even for flowering. And make sure that the high temp of 78 degrees is measured right AT the canopy of the plants. Oh, one more thing, you can give them silica blast to make them stand up to high temps better.