Dont tell anyone but I got a one time steal on a large tub (16 lbs???) of ph down. I thought to myself, this will be the last time I ever have to buy ph down. I had been using the orange bottle, is that GH? My dry powder is from the same company, again I'll guess General Hydro. I had no idea of the ratio so I just filled the old 1 liter bottle of ph down with water and started adding powder. I had to add a lot before I was happy, but at least it became more concentrated then the old stuff. For whatever reason about the same time I started using it, I also started to get massive fluctuations in ph as well. It was getting so bad that I was adding in a good portion of my ph brew every day. I swear the more I added of this damn powder the more my ph rose the next day. WTF??? Maybe it was the powder, maybe it was something else I dont know, but man did I ever have to use a lot of it. It started to worry me so I researched other means of controlling ph. Currently I use so little acid that I can go 3/4 days before needing to even think about it. Many times even then I dont adjust, I just think continue to think about it. :P

I'm currently using the GH powder series (Maxigrow & MaxiBloom, Koolbloom) which supposedly has a ph buffer in it in addition to using coco as the medium. I flood my table every 12 hours now instead of every 15 minutes or so with hydroton. My water is cleaner then it's ever been, the ph fluctuates so very little now and my plant growth has been much more steady. I'm not saying yours will get better, I don't think I can judge that, but since I was having some lingering problems with ph, over watering and such, all that has now gone away with my current setup. The plants are much happier then ever before since they have a much more stable environment then what I was providing before.

Ph adjusting is a nitemare.