A properly maintained pool is one that is visually and biologically clean. "You can tell if it’s visually clean, just by looking at it. But in order to tell if it’s ‘biologically clean’?" You must use a test kit, to measure your pool’s Sanitizer, Alkalinity and pH levels. If you maintain the proper chlorine and pH levels, bacteria and algae will be killed, and your pool will be "biologically" safe.
Complete water analysis available in just minutes.