Chief that's what I do. I use tap water and it's 6.0 on the scale and it ppm's out at 90-100. What happens is I add the nutrient and cal mag and wait ten minutes or so and add acid to bring it down. And it goes to 5.5 and the next day I check it like normal and it 6.1-6.3. I wasn't so worried about that as the mag and cal are better taken up at this ph. So I lowered it again hoping for about 5.8 which is still good. And I was hoping it would stay stable. Nope it ran back up to 6.1-6.3. The plants are using water and nutrients so fast at this point. There using at least 3/4 to a gallon a day. And there taking up nutrients really fast. At about a tsp of nutrients. Because I have to add that back to bring the ppm back to 900. Before the calmag I didn't have to use acid or anything the acid in the nutrient was enough. I didn't even know I was suppose to use calmag the whole grow. I thought the tap water had enough in it. The plants didn't seem to look deficient to me. Do you see something I don't?