Thanks, James -- my reputation for being "Mr. OCD" sometimes gets me in trouble, and I shouldn't have overreacted. Even better would've been if I reminded myself that you have a much longer track record of good cactus-growing than I do before I put up a detailed post which really wasn't apropos to your particular approach.jp29 wrote:Please do not do that, Steve - you do contribute so much thought provoking information.
Since I've had a few inquiries about sharing my success with acidification, I'll post a new thread on the Cultivation forum. If I can keep my tendency toward blathering under control, then whatever I have to say may be helpful if my experience is of some benefit. I also don't want to be the author of misinformation -- such being the case, I hope that you're still willing to have Dr. Wheeler run a test in his lab comparing the results between a pH meter and the type of colorimetric indicator kit under discussion. This isn't merely to satisfy my curiosity, because the results and their implications will have to be reported before we know whether or not there are major discrepancies in the methods people use when they acidify their water. While Dr. Buxbaum's book is excellent even after all these years, digital pen-style pH meters hadn't been invented yet, and the meters available to hobbyists these days are much simpler than the elaborate lab equipment he would've basically described. Much less expensive too, although it depends on selecting a meter that produces reliable results. Without going off-track about the relative merits of different meters one can buy, I'll just state that since people should know they have a choice between using a pH meter and a colorimetric indicator, any major discrepancies between the two need to be factored into what I present.
You may have misunderstood me, and I'll have to own that one. The desired pH for acidified water ranges from 5.0 to 6.0, so that's a big enough range to work with regardless of having to worry about day-to-day fluctuations in the pH of our tap water. The exercise I went through in my (overly) detailed post was merely a demonstration. What I do in real practice is less complicated than you perhaps thought, and the final pH of my acidified water/fertilizer solution is somewhere within that desired range. By the way -- while I'm satisfied with the results of my initial slurry test, I'll run another one which I'll discuss at the appropriate time. I do agree that the pH of what comes out could be as important as what goes in, especially to growers who add limestone (or in some cases Gypsum) in their mixes for certain cacti.jp29 wrote:I think you are getting far too wrapped up into Ph testing accuracy, Steve. There are simply too many fluctuations in pH values throughout any given day to require that degree of accuracy.
I'd be grateful for any light Dr. Wheeler can shed on the pH meter vs. colorimetric indicator tests, and when I cobble my acidified water presentation together, I'll definitely put the results to good use for whoever is interested.
Thanks for bearing with me, my friend.