Here is my mixed SPS/LPS 150g. All I run is an ATS and a good Protien Skimmer. I don't dose, have fancy equipment, just good lighting, and good removal of excess nutrients, lots of live rock. I grow hair algae where I want to, to remove excess nutrients. I have not done a water change in over a year. When my salinity goes low, I just put fresh sw mix in my ato to slowly bring it back up. I actually have to start removing corals to make room for others to grow.