First time indoor grow so may change up, but for now using tap water ran through a Pur faucet filter. Only thing I can’t quite grasp is why tap goes in PH 6.9 and comes out PH 8.8. after being filtered? But then only takes a few grains of citric acid to bring right back to 6.5. Was thinking those filters used minerals to soften the water, but can’t find anywhere that anything is added. Can removing chlorine and impurity’s lower PH that much?