I am bringing up a new Water Farm... While I wait for babies to arrive, I am just recirculating plain RO water in the WF. The media is 50/50 Hydroton/Higromite. The RO water went in at about pH 6.3, but keeps climbing. I have added pH down to it an oz at a time on several occasions over the past couple of weeks, knocking it back, but only for a while. I did rinse and soak the media quite well before loading it into the WF, and I ran it for a few days on plain tap water, then flushed and ran some bleach water for a day or two, then tap water again for a few days, then went to RO and started montoring pH, which continues to return to high levels (7+). I'm thinking this may be a normal thing for new media. Can I expect the media to ever neutralize? Am I in error to believe that the media should not affect the pH in this way?
Im using the powergrower which is just a bigger waterfarm. I was having the same problem with mine. The Hydrotrons take a while to get to a safe ph. At least you are discovering this prior to putting a plant in it. It took me about 8 days of constant ph adjusting and about 4 complete water changes before it finally stabled out. I was putting water with a ph of 4 in there with the RO coming out at 6.5 and then it would just drift up to over 7. Just keep trying and you will stable it out. Rinse everything down really good, and when you think you are done, do it again. I rinsed the hydrotrons pretty damn good and they were still leaving dust in the water(which was causing wacky ph)