Quote Originally Posted by Chabnoc
My last grow. I pretty much only had to ph my res when I replaced the water/nuts.
If your tapwater is 'hard' or has a lot of dissolved minerals, often limestone, this will cause the pH to rise. Nutrients also often include pH buffers, which will hold pH steady for a few days but will react with other things in tapwater and become less effective over the life of your tank of nute solution.

You can eliminate that problem by using distilled, RO or other demineralised water- or you can just live with the tapwater and just know it will need to be pH corrected.
Al B. Fuct Reviewed by Al B. Fuct on . First time with rock wool. This is my first time useing rock wool. Seems to be working pretty good so far, but the PH is going up each day. I am useing R/O water, and I ph it to about 5.5, by the next day it is up to over 7.0. It is only been 3 days now. Is this normal, and if so, we it get better with time? I am useing the same nuts as I used the last time, and my PH was real stable. Thanks for any help. Chab. Rating: 5