I recently noticed this getting worse and this morning it was bad.. I dont post much on here but read/study almost everyday.. Ive searched and searched and cant find anything that matched whats going on.. This is week 5 in DWC.. 630ppm.. GH nutes.. 800hps in cooltubes.. temps @ 72. I've been keeping the Ph at 5.8-6.0 but this morning I did notice the ph was at 5.0 (corrected it to 5.9), I havent checked it in a week.. So im hoping this was just a ph issue.. But whatever it is only effected the top leafs of the plant.. any advice would be great! Thanks in advance!!!