There are five basic swimming pool chemicals in common use. These are, chlorine, used to kill bacteria, algaecide to prevent plant spores from turning your water green, PH+ for increasing your waters alkalinity and PH- for decreasing it. The last chemical used is a flocculent whose purpose is to attract particles in order that they form into clumps large enough to be removed by the filters.
It is vital that you maintain this between 7.2 – 7.6. If you are out by only a little the efficiency of your chlorine can drop by 90 per cent allowing infection to take hold in your swimming pool. It’s a very simple thing to do and no reason exists for being unable to do it. Normally you will find that the ph is increasing, requiring the adding of a PH reducer.
On a regular basis you need to backwash your swimming pool filter. After a couple of weeks or so, sand filters become blocked with the various things they have removed from the water. This includes, dead skin cells, hair, oil, insects, dust, and anything else which has fallen into the swimming pool and been picked up by either the skimmer or crawler.
Algae are tiny plants that bloom and grow in swimming pools if nutrients are present and a sufficient level of free chlorine is not maintained. If uncontrolled, you can go from sparkling water to pea soup almost overnight.