Without the proper pH balance, plants will not efficiently uptake nutrients; it's one of the most overlooked aspects in effective gardening. pH-Up and pH-Down helps your plants achieve optimum absorption. Without the proper pH balance, plants will not efficiently uptake nutrients; it's one of the most overlooked aspects in effective gardening. pH-Up and pH-Down helps your plants achieve optimum absorption of nutrients by adjusting the acid/alkaline balance of your water.