really just depends on what ur looking to get out of ur tank? no info on that . . . if i had another co2 i would still throw it on a low light tank just a little extra co2 really helps, but its all up to what you want out of it and whats in it ect ect. are u tryin to just go for low tech no co2 an any "fancy" things or just low light? low light doesnt have to be low tech.