Damn i had the same problem, they started rapidly producing this white shit on the leaves, i could wipe it off with my finger, at first i freaked out and took a couple leaves i could sacrifice, then i sprayed it with antibacterial soap, now its all gone and theres only a slight bit of leaf burn, i also dumped a good 1/2ounce of guano on each plants soil, they took right the fuck off, and their pretty purple with this damn new england weather, i hope i can make it into october, 3rd week flowering, no ferts besides guano, in canadian gold potting mix, ones topped and one isnt, the topped one isnt so strong or bushy but the untopped one is god like