Biobizz ph down is notorious for having the ph drift up over time. Your soil isn't buffering. Next time add dolomitic lime to your soil mix and it will automatically buffer. Sorry for your loss. Next time instead of buying a bunch of plastic bottles of nutrients that are 90% water, and not ecologically friendly get a nice dry nutrient you can mix with water yourself, or make your own nutrients like fish emulsion, banana water, or comfrey tea. Recipes found online. You'll have healthy plants, money savings of 60-90% depending on what option you go with. If you just keep following directions, immitating without knowing anything about plant biology and gardening 101, and let the marketing bs shape you into the perfect customer, the perfect zombie grower... you'll be like 99% of the other grombies on here emptying their wallets to grow a plant being exploited through being locked in to repeat purchases for every grow. There is no such thing as cannabis specific botany, no more than there is Swedish botany or apple tree botony. At the end of the day the plants have the same needs. Forget everything you think you know or learned. Wherever you got your info so far, never trust them again. And avoid any cannabis specific information especially from seed suppliers and websites with commercial cannabis product sponsors. Just stop. Educate yourself first, then start gardening. Put the horse in front of the cart. Remember, quality weed starts at the seed. If you are buying from a commercial supplier, you just failed at the very foundation. If you need help, dont rely on asking the unconcious masses of grombies. You can write me if you have trouble finding decent, basic gardening info or basic plant biology info. Merry Christmas.