My research led me toThanks for the detailed write up! Something I'm considering more now. What sort of tetras do you have that come from harder water areas? I naturally have hard water here in London UK so a bonus in that respect
Black Neon Tetra-Hyphessobrycon herbertaxelrodi
Red eye Tetra-Moenkhausia sanctaefilomenae
Both of these are found in varied different waters parameters in the wild from the low side of 7.0PH up to 8.2PH.

