The author of the ref'd article suggests reducing calcium or GH to reduce pH. GH/calcium/magnesium has no, repeat no effect on pH. KH/carbonate hardness/alkalinity directly controls pH in the absence of organic acids or added CO2. Review your chemistry for clarification.
RO has no effect on pH? Try checking pH on KH 10 water, dilute 50:50 with RO and retest pH. The KH will be down to ~5, the pH down proportionally to the log function. The pH is a concentration effect, dilute the alkalinity, reduce the pH due to the reduction in concentration of bicarbonate/carbonate ions in solution. Again, review your chemistry. The author suggests that the TWP is the only available practical technique for reducing mineral content - as I said, rather obviously, or perhaps obliviously, omitting any mention of RO.
The article is not totally without merit, but I would never suggest it to anyone who needed assistance in understanding tank chemistry, as the author has obvious lacks in his own understanding of what he is attempting to clarify. The suggestion for use of massive amounts of crushed coral buried under the substrate with no consideration of the starting alkalinity of the water illustrates that quite clearly, or of material contact with the water column. That may a recipe, but IMHO not a very good one, and it certainly is not chemistry.
I am both a senior research scientist and senior analyst. I hardly need assistance in evaluating a purportedly science-based article, but thanks for the offer of assistance via your site.
