GH=General Hydroponics pH up and down is a solid product and very strong so you need only use small amts which makes it last longer than some other brands. Personally i only use their up cause i use R/O as a base which is about 7.0 as is so if i need to lower it a fraction even on water only days i just add a 5% nute solution to dial it just right. An 8oz bottle can last years. If you use tap with a high pH i suggest AN's Barracade to lower pH,much better all the way around,lil pricey but iMO the way to go.
Any time bro,direct any questions you want on our thread in the beginner section "So you want to grow MJ" VERY fun thread,ENJOY!!