based on your usage (2 people a few times a week) the nature2 is actually pretty simple...you will use renew/mps/shock (all the same) after each use to oxidize your waste (good idea to keep cover open for a couple minutes when using shock) and on top of that a small addition or two of chlorine a week and that basically covers it as far as sanitation goes...now remember aside from sanitation you of course will also need to maintain proper pH, Alk, and calcium levels and occasionally hose your filter off as well and that really boils down spa maintenance in a nutshell....keep your water balanced, keep it sanitized, and keep your filter clean....easy peasy