Additionally, all the kids go back to school, Major League Baseball Playoffs loom just around the corner, and Professional Football has started back up. All of these things can serve as distractions from pool maintentance duties.

Warmer pool water at the end of the pool season means sanitizer levels may drop faster and if a pool gets neglected for perhaps even just a day or two longer than normal, that warm sanitizer-free water may become an excellent breeding ground for algae.

Water temperature affects water balance:

• The amount of chemicals needed increases with warmer pool & spa water temperatures
• Calcium is less soluble in warm water and is more likely to buildup on pool surfaces
• Chemical usage increases as temperature increases

( source )

“Oh, well, we use an algaecide in our pool so we won’t have any problems.”

Not exactly correct. The majority of algaecides on the market serve as ‘last lines of defense’ against the growth of algae and it gets used up faster when the water gets warmer, too.

In addition to the use of algaecides which help to prevent and/or retard the growth of algae when sanitizer levels drop, pool owners have another weapon they can use when attempting to keep various forms of green algae, yellow/mustard algae, and/or black algae from growing in their pools: Pool Check Phosphate Check.

Although algae sunlight, humidity, and a lack of chemicals to prevent algae make for a great algae breeding ground, algae also requires a nutrient called phosphate. In a nutshell, the amount of phosphate present in body of water dictates how much algae could possibly grow in that water. Therefore it stands to reason that pools containing large amounts of phosphates stand the greratest chance of having serious algae problems when other water conditions make algae growth possible.

We have also read that pools with high phosphate levels “produce resistant algae and interfere with the sanitizing property of chlorine.” ( source )

“Phosphates sound like trouble. How do we know how many phosphates our pool contains?”

Up until a few years ago pool owners had to send their water samples off to a laboratory for phosphate content analysis. Now however, the Pool Check Phosphate Test Kit makes it possible for pool owners to measure the phosphate content of their pool water in just 30 seconds. With a detection range of from 0 ppb up to 2,500 ppb the Pool Check Phosphate Test Kit makes phosphate testing at the beginning, middle and end of the pool season simple and affordable.

As a general rule, pools ought not have phosphate levels above 100 ppb. If you limit the amount of nutrients needed for algae to grow, you effectively limit the amount af algae that can grow.