1st Auto Grow LSD-25 & Cream Coookies

So week 8 some problems showed up on both girls. LSD-25 is a little further along in bud production than Cream Cookies, which sounds about right. LSD-25 had some bottom leaves yellowing, which fell off without any problems. Also the some of the leaves at the top are starting to yellow with burnt tips (I thought that may have been heat stress last week, but not sure now). Cream Cookies is also showing some problems, with brown "rust" spots throughout the plant. The the top portion of the plant is a lighter shade of green now. Looking up nutrient deficiencies, looks like it could be a couple of things to me, so not sure. Anyway, I flushed them today and going to feed them a little later on before the lights go out..