So I am new to salt water anything. I have had fresh for many years but have also worked with some very large salt water animals, mamals and other marine life. I am thinking about starting up my first salt water tank and working my way to getting an octopus. I have worked with several from cali to seattle. I am totally starting from scratch on this one. What I mean by that one is first comes in the brand new water heater. I have no problem getting that one what I am wondering is what would be good to use to purify the water coming out of said water heater? I want to be able to know everything starting from themost basic and taking it nice and slow and reading everything but I did want help with this one question.