Hey well i checked my ph level from my tap water using this PH tester i orderd from walmart, were you fill it up half way put in 3 drops of ph tester into the liquid shake it up and it turns into a color and you find it on the chart. My ph was 6.4 from my tap water then testing my aquarium water it was 7.2. I have alot of sand in my tank and a small rock could this affect it? btw the aquarium was filled up with the tap water Ok thanks.