Hi. I joined this forum to try and get some info on a plunge pool I use at a holiday home. It's 10 feet by 3 feet deep. Usually in the summer I arrive. Fill it. Add chlorine and run a pump then monitor level and 2 weeks later I drain it. No probs. however I want to set it up in June then I won't be there for 4 weeks. If I add lots of chlorine and cover it with a dark cover and leave the pump off will the water be clean when I get back ? Thanks. Rob