its anquarium ph tester, and im not using the aquarium ph up or down, hence why i said i dont have up or down. but from what i think i remember from here the correct PH is 6.5-6.8 for optimal nutrient intake. and the chlroine in the tap isnt harmful to the root structure of the plant, but instead acts as a "germicide" i believe that makes the root environment more sterile without harm.