if I believe my own hubrisreverse;3017640; said:David knows best...............
seriously tho, what I know I have learned the hard way over about 33 years of keeping Amazon fish, and a long career debating on various forums LOL so if I know more its probably only because I have a few more years on me than others, and I am a slave to my curiosity, each answer leading to another "how?" or "why?", that and too much time on my hands sometimes!
If you do decide to adjust the pH using acid ( muriatic acid is commonly used for this, available from swimming pool supply stores) do it in a separate container 24 hours before you need it to allow any pH 'bounces' to reach equlibrium before adding it to your tank, so if you eff up you have done no harm. Wear gloves and goggles and have an accurate digital pH meter. A much better and safer but slower way is to use r/o