RODI water, RODI Kalkwasser for all ATO water and no fish with my corals. As most people have fish, I recommend using no dry food, not flakes, pellets or freeze dried. Use only live food and good quality frozen foods. Thaw all frozen foods before use, and feed only the particles not the fluids. When phospahtes, despite your best efforts, are still a problem then use ferric hydroxide. I use Drs. Foster and Smiths store brand when needed, and only when needed. It is only a bandaid not a repair. If you do not fix the problem it will continue to come back. My only exception for this is when getting new rock and sand, then I use Ferric hydroxide constantly for 10 to 14 days.