Quick overview. Planted 125L tank with a good sized external filter (Fluval 307). Injected CO2. Reasonably lean dosing. Water params ~ 50/50 RO/Tapwater (hardwater); GH 12, KH 6,NH3 0, NO2 0, NO3 ~20ppm, PO4 ~0.5ppm. PH between 6.8-7.8 depending on time of day (changes with CO2 levels)...