The water in our 40 gallon freshwater aquarium was pH 6.6 yesterday (tested at Firdale store). I added 2 tsp of pH
7.0 Seachem Neutral Regulator last night. This morning I find the pH is even lower (pH 6.4). Any explanations? Does Neutral Regulator lose effectiveness with age? (This batch is 5 - 10 years old but looks fresh.)