PH up and PH down... I just use pure lime or lemon juice to lower my PH - luckily I never need to raise my PH. Never had any issues using lime or lemon juice although some people might disagree, but it works for me. PH tester is vital, calmag is vital. Slow growth can also be caused by poor genetics. I am growing Dark Purple Auto by Delicious Seeds and it's 2 weeks on Thursday. It has 3 sets of leaves but it's miniature lol where as my Purple Auto by Original Sensible is just over 2 weeks and triple the size of the Dark Purple. Probably a good strain if you're wanting to do a micro grow inside a computer case! Lol. It was a freebie so, what the heck! [emoji106][emoji38]