The Viagrow ph Test Kit comes complete with pH up & down liquid nutrient adjusting solution & is formulated using the highest food grade quality & includes a broad range pH Test Kit Which will indicate the pH value of your nutrient solution. While the liquid pH down solution uses food grade phosphoric acid & is safe for all food crops, the pH up uses food grade potassium hydroxide & is safe for all food crops. The Viagrow ph up & down are highly concentrated so less is needed for use as compared to most brands. Viagrow pH up & down can be used in all growing mediums - soil, soilless, hydroponics, or to adjust a foliar application. Maintaining a proper pH is an important part of growing healthy plants & Your broad range pH Test Kit will measure pH as low as 4 & as high as a value of 10 to grow the most vigorous plants maintain a slightly acidic pH in your choice of growing Media, It is recommended that the pH for most crops fall between 5. 5 & 6. 5 use moderately. Add 1 Drop of adjusting solution at a time to the plant nutrient solution & then test the pH. Repeat application & test again until appropriate pH level is achieved.