KH, PH, Co2, substrates, fish and plants !
My tap water is PH 8.2 / KH 11 / GH 13. I have been reading that high KH values reduce the waters ability to absorb Co2, and this is reflected in those PH/KH/Co2 charts.
The general advice seems to be to not 'fight' the parameters of your tap water as this often results in unstable conditions, and the better approach is to stick with your tap water and choose plants and fish which like those parameters.
Based on the above, and the fact that I will be injecting pressurised Co2 in to my tank, is it a good idea to use a 'complete' substrate such as ADA Amazonia which will lower PH & KH?
My understanding is that this could be good because it will increase the waters ability to absorb Co2, and ammonia will be in a less toxic form, but it is still altering my tap water which goes against the general advice I have read. What confuses me even further is that when I do a 50% WC with my tap water, the chemistry will be different from what is in the tank because of the substrates influence, and surely this will be causing those unstable conditions that I was supposed to be avoiding.
So in summary my questions are:
1. Should I chose an inert substrate, or one which will lower KH & PH.
2. Should I be looking to lower my KH and PH values for better Co2 absorbency and less toxic ammonia, which in turn will allow me to keep some species that I desire which prefer slightly softer water....
OR should I be choosing fish and plants for my harder tap water and just accepting that Co2 absorbency will be more difficult and more toxic ammonia could exist ?
Sorry for the length of the post, I would appreciate any advice to resolve these conflicts in my thinking.