hi guys new boy to the site lol! need some help plz! first thing first. im new to this just thought i'd do a little grow for me and my mates, got a skinny tent 400w light a 4 pot wilma and carbon filter and fan. and a little fan inside to circle air flow! my first question to you guys is: its three weeks 2moz since i started and my tallest plant is about 9-10 inch and about the same dimension as the top of the wilma pot. at what time should i really switch to 12/12 because my table is tellin me around now! but i thought u left it on 18hrs until ur happy with the size??? also some of my leaves are going slighty yellow and dying a bit at the tips. i spoke to the guy at the local shop he told me my ph was prob wrong so i invested in a ph meter. well worth it loads easier! my ph is between 5.9 - 6 he told me keep it at 6 at this stage. the problem isnt getting any worse really but its still there any advice. im using cocco feeding ever 3hrs for 30 mins i was doing 15mins every hour but was told tht prob was a bit much! i only use cocca a and b and only put in what the table tells me, i also have tht cazylysm stuff if thts how u spell it lol!