Its hard to see in the pic but 1 of every 10 has a brown tip and is curling. My temp and humidity are always on point. My set up is in a spare bedroom. Beautifully clime controlled. I did lots of research. I think its either old pistols, original ones potentially dying off or it maybe drainage issues. I ph balance always, use spring water, molasses and food liquid nutes(diluted for autos). Temp goes 22c-26c between night and day, rh 57-67.