Your water has stuff in it that affects the pH. Some of the stuff wants to push the pH down; others want to push the pH up. So you kind of have an up/down battle going on. Whatever is in your tap water is stronger than your pH down, so the pH gradually rises. This is completely normal. When you add the nutrients, they act as a strong buffer to bring the pH down, counteracting whatever is in your tap water buffering it up. That's why your nute solution is more stable than your plain water

PC :smokin:
PharmaCan Reviewed by PharmaCan on . Rising ph level? Our tap water comes to us at a ph level of right around 9.0 with 20 ppm of tsd. I use PH Down to lower it to about 5.8 using a calibrated digital meter. I store it in an opaque, 3 gallon container, placed in the grow room. I was trying to get my plants run-off to be around 6.0, so i was checking the water before i used it. It seems to have gone up over a full point in about a week. The room has a 1,000 watt mh in it now. I was wondering if the PH Down is light sensitive? Anyone ever noticed Rating: 5