I sometimes use notg and mixed with no ph up is usually 5.9 or so there's no way. id invest in an apera ph meter. the lowest ive personaly seen is buddha bloom and that was a ph of 4. SomethingMy ph keeps reading 1.78 and I keep adding ph up and nothing. I did about half my big bottle for just 2 gallons and nothing also this is the first time I am using this nutrient line and use fox farm and my ph up worked fine