slowly creeps up as week goes on. Hydro you really dont want PH above 6.0 and if you have a Calmag issue then get some Calmag to add to res. I have been cheating a lil with my mother plant as I thought I had a mag def so started a low dose of epsom salts to see if was correct and we had improvment. Calmag is on my shopping list and dont believe the hard water formula will do what your looking for. My tap starts right around the 7.0 mark