Effects of evaporation and pool chemicals on your pool water...

Evaporation

The mineral and metal content of your pool water increases each time water is added to your pool. Evaporation removes only distilled water, so the minerals are left behind in your pool. The sum total of all the dissolved material in the water is called TDS. It includes hardness, alkalinity, chlorides, sodium, sulfates, salts, and just about everything that has been put into the water.  – When your water becomes oversaturated with these dissolved solids, phenomena like salty or bitter tasting water, colored but clear water, algae growth in high chlorine environment, corrosion of metallic parts, cloudy water, eye and skin irritation, and false readings of chemical tests can occur.

Swimming pool chemicals

Some of the pool chemicals that are used to keep your pool sparkling clean and clear also carry with them some compounds that add to the TDS and will start to interfere with the normal reactions we come to expect in balanced water. Phosphates, metals, calcium, salt & cyanuric acid are all included in some pool maintenance chemicals and as they too will not evaporate, they will increase until they start to interfere with normal water conditions. Things like staining, algae, high chlorine demand are all possible circumstances these increased chemicals can cause.

Remedies & Prevention

Simple water tests can help determine if your pool water needs cleaning or replacement. Consult your pool store or pool service professional for specific treatments for your pool. You may want to also consider the types of sanitization chemicals used and your water source on your pool to slow down the inevitable rise of your pools TDS, but water replacement or water cleaning will continue to be a crucial part of your pools health here in the desert southwest. After your pool is treated and refilled, consider pool surface protection products as an ongoing prevention.