..........grow in the pool plumbing if you don't use the lines. Example, I have a sheer descent and 2 water Lion features that I do not use everyday, I guess no water will circulate in those pipes until I open them up. So, could I get by 2 or 3 days with out circulating water through them? I have probably gone weeks with out opening the valves and no Algae or CCs (knock on wood). Also, how about the vac suction line?. I have gone days without opening that line as well.