Pool Chemistry Special Problems

1.      WHY DOES POOL WATER TURN GREEN? Because of algae growth. Algae may impart a greenish, reddish, or brownish color to the water. It also makes the bottom and sides of pool slimy. (Follow Step 3 below immediately).

2.      WHAT IS ALGAE? – A microscopic plant life that thrives and multiplies very rapidly in warm, unchlorinated water. Algae causes slimy patches and stains to develop on the bottom and sides of the pools.  There are many strains of algae, but the most common are the green, reddish-brown or black. An algae condition will reduce chlorine residual and greatly shorten filter cycles.

3.      HOW DO YOU REMOVE ALGAE FROM POOL? – By super-chlorination (referred to as shock treatment). This is done by adding three to five times the normal amount of chlorine recommended for the amount of water in your pool. This amount of chlorine will kill the algae and it will be removed by the filter and by vacuuming.

4.      WHAT IS HARD WATER? – Water that contains large amounts of calcium or magnesium is referred to as hard water.

5.      WHAT EFFECT DOES HARD WATER HAVE ON THE POOL? – The presence of calcium particularly can lead to the formation of scale (calcium carbonate), if certain factors in the water such as pH and total alkalinity are not controlled. The scale deposits itself on the filter grids, piping and on occasion on the pool inner surfaces. These deposits reduce filter efficiency and in extreme cases, the deposits on pool walls can scratch bather’s skin.

6.      WHAT IS “IRON WATER” AND HOW CAN IT BE CORRECTED? – The presence of iron in natural waters occurs at various locations throughout the country. When a pool is filled with water containing iron, a reaction takes place upon exposure to chlorine that turns the water brown. This discoloration is sediment of insoluble iron that will stain the pool and will cause clogging of the filter.

7.      HOW DO YOU REMOVE IRON FROM POOL WATER? – The pH must be between 7.2 and 7.6. Turn filter off, use alum powder at a rate of 1 pound per 3,000 gallons of water. Weigh amount of alum needed and place in porous bag and drag through the water until it dissolves. Let pool stand 24-36 hours. Set filter for vacuum to waste and attach vacuum and clean pool bottom. When ready to use pool, check pH because alum in water may lower pH below 7.2 which means soda ash should be added to the water.