You check the health of the water through regular testing. Especially if you have a kit that can measure CC (combined chlorine). If you get a CC reading higher than 0.5ppm, that can be a sigh that something is brewing and you need to shock the pool. That is one reason we encourage people to buy the Taylor K2006 kit as it can measure CC.
Losing more than 1ppm of chlorine overnight from sundown to within two hours of sunrise the following day can let you know that something is consuming your chlorine. Another sign of potential problems.
Another sign that you may need to shock the pool is if you let the chlorine level dip below the minimum level required for your CYA level. (If you haven't already done so, take a look at the Best Guess Chlorine Chart in Janet's signature above.
These are not the only signs, but some of the main ones. Hope this helps.
Bookmarks