spurr, thanks for the citric acid stuff, im going to start a thread and will repost it there.
Sounds good, it would get lost here you're right. FWIW, I use citric acid I buy from a wine and beer brewing shop to drop water pH from 6.00 to 6.10. Dropping pH to that range allows me to add a decent amount of critic acid which is my goal.
I don't use citric acid to drop pH but it's a side effect of using it to increase the Krebs cycle, organic matter mineralization and P anion solubility in rhizosphere and soil solution. As has been discussed elsewhere, for organics a water pH from 5.5 to 7.5 is fine, even up to 8 is OK, and water pH has very, very little effect upon pH of media (rhizosphere and soil solution). The alkalinity of water is what has much greater effect upon pH of the media than the pH of water; and roots/microbes have a great effect upon pH of rhizosphere and soil solution.
Water with high alkalinity has pH over 7 but water with pH over 7 doesn't necessarily mean high alkalinity.
In hydro with chems water pH is much more of a concern, as well as alkalinity and level of ammonicial N (ex. ammonium, which makes roots release acidic H+ protons lowering pH) and nitrate (which makes roots release basic bicarbonates increasing pH).
On the topic of ammonicial N, that is one reason why fungal rich media has lower pH. Because fungal rich media often has greater pools of ammonicial N than does bacterial rich media; thus when roots take in the ammonicial N (mostly as ammonium, NH4+) they release acidic H+ protons. Bacterial rich media often has greater pools of nitrates (NO3-); thus when roots take in the nitrate N they release basic bicarbonates increasing pH.
P.S. I have other papers on the topic of critic acid I can post in your thread you will start.