Citric acid is a natural Ph corrector, and in addition to being used to control pH in nutrient solutions, it can also be used for cleaning ducts or water pipes.
Lemon juice concentrate has a pH of 2.2 so that when you use it, supply small amounts.
Small doses are recommended until the desired Ph level is reached.
Lemon juice concentrate 55BX with SO2.
Permitted use in organic agriculture .