Just a feedback on
bvy's method. I'm doing some small scale commercial developing in ATL1000 and I've been using it since february with 10L packages and it works awesome. It is more expensive than replenishing but 40L packages is 50€ + 10€ for starter here in Serbia. I can squeeze about 400 films so the price is around 0.15€ per film.
My combo is
8000ml H2O + A + B + C + 525ml H2O + (2713 H2O + 393ml starter) i mix that in 20L tank with spigot and fill dark brown hard PET 1L bottles to the brim. One i'm currently using is in the fridge others are in cold basement.