i'd actually use around 10 drops of the ph reagent to get a darker color that's easier to read. making 4dkh is very simple. just buy a gallon of distilled water or RO, water hardness testing kit, baking soda (pure sodium bicarbonate), and a plastic disposable fork(can be metal). the fork is used for small amounts of baking soda. scoop the tip of one of the prongs for a minute amount and add to the water, test, and then adjust as necessary. shouldn't take you more than 5 minutes.