hey bro:-) looking good man. that may be a little nute burn? just use quarter doses maybee upping it if needed and go ,feed,feed,just water and so on.have yoor nutes got full trace,micro nutrients etc? im not a good trouble shooter eh:-). im not one of these that can just look at a plant and go ,OH WELL YEA YEA THATS CLEARLY A ? DEFICINCIE:-)LOL i never have been i know you basiks like N ,P, calcium,magnesium etc but yours look all ok dont sweat it over tiny bottom leaves bro .your doing good.just check for micro nutes in ya food mate is all i can say.oh and for a quick fix of good shit just do a very simple compost tea? like? 1,litre of good soil in 15,20,litres of water and bubble,or stir and sit it for 24,hours to leach all the goodness out the soil into the bucket of water then SHAZZAMM. percy plants:-) also use this as a foliar spray for the quick fix on foliage. if im hard to understand im sorry.just stoned.let me know.and ill tell. you in a better way .keep up the good work eh mate.u doing real nicely.