My name is Ken Cordero and I recently moved to Mason from the Sacramento area of California. Some of you may know my Sherrie Cordero. We moved here in August and she teaches part time at Mason High School (go Punchers!).
I have nearly 44 years experience in the swimming pool service and repair industry, and after selling my business in California, I hope to do a scaled-down version of what I did in California here in Mason. I recently had the pleasure of meeting one of the local pool owners who was having algae problems with his pool. He has had his swimming pool for many years and has far more knowledge than the average pool owner. I like challenges, so I brought several of my test kits with me and tested his water.
The water was clear and his chlorine floater was full of chlorine tablets; but, my tests revealed that though the chlorine level was acceptable, it was all in what is known as a "combined state." The FAC, or free available chlorine, was 0 p.p.m. (parts per million). Free chlorine is that which available to continue to kill pathogens (disease causing bacteria) as they are introduced into the water. Combined chlorine is chlorine that has combined with ammonia or nitrogen and is only about 10% as effective at killing pathogens as free chlorine. Chlorine works by slowly poisoning and killing bacteria, and can be quite effective at keeping pool water clear and algae free at levels between 3.0 and 5.0 p.p.m., if the chlorine is in a "free" state.
Another problem my test kit revealed was low p.h. The p.h. symbol stands for % of hydrogen, or power of hydrogen. The more hydrogen ions in the water, the more corrosive the water (low p.h.). The more hydroxide ions in the water, the more scale forming the water (high p.h.). The ideal p.h. of pool water with a plaster finish is 7.5, and is slightly alkaline. This helps to protect the cement in the finish, yet, is well below the scale forming range.
The p.h. scale starts at 0 and ends at 14. Since the scale is logarithmic, each point value is 10 times greater than the preceding value. For example, a p.h. of 8.0 is ten times greater than the preceding value. Low p.h. can cause eye and skin irritation, and can slowly dissolve the cement in the plaster finish. Low p.h. will also corrode ANY metal in the pool system (pumps, filters, heaters, metal plumbing). A continually low p.h. can cost the pool owner thousands of dollars over time.
Another problem I found was a low total alkalinity. Total alkalinity is primarily a measure of carbonates and bicarbonates, and is an indicator of the buffering capacity of the water (the ability of the water to resist rapid changes in the p.h.).
Alkalinity is important in water balance because low alkalinity usually leads to low p.h. and corrosive water. High alkalinity can cause high p.h. In most cases, calcium carbonate will precipitate out of pool water at a p.h. of 8.3 or above and form scale on the pool surfaces. High alkalinity can also cause turbidity (cloudiness) of the pool water.
My pool owner's water hardness was at 380 p.p.m. and was in the acceptable range of 200 to 400 p.p.m. Water hardness is primarily a measurement of calcium and magnesium in the water. It is one of the four components of water balancing, along with p.h., alkalinity and water temperature. Water hardness is the one variable in water balance that tends to change the least over time and has the least affect on water balance.
My test of the pool owner's chlorine stabilizer level revealed that it was very high (approximately 200 p.p.m.). At that level, it's just and educated guess as my test kit is only accurate to 100 p.p.m. Chlorine stabilizer is also known as conditioner, and to to those of us in the industry, cyanuric acid or iso cyanurate. The importance of this chemical is that it is able to bond with the chlorine molecule temporarily and shield it from the ultraviolet rays of the sun. This means that the chlorine will stick around longer to do its job. The downside to cyanuric acid is that when there is too much of it in the water, the chlorine will last a long time, but won't be very effective. The trade-off is longevity versus activity, and like almost everything else in life, the proper balance is critical.
A major cause of algae in pool water is the presence of phosphates. Phosphates, or Ortho phosphates, are found in many outside sources of pool contaminates; but, the primary source is from certain fertilizers. Phosphates drastically reduce the effectiveness of chlorine, and a phosphate level of as low as 200 p.p.b. (that's parts per BILLION parts of water!) can lead to an algae bloom if the pool is low on chlorine. Phosphates can only be removed with the addition of a special chemical designed for that purpose. My pool owner's phosphate level was 750 p.p.b.
This article was originally longer and more technical; but, I have mercifully shortened it. My desire is that this information will help you pool owners in the Mason area take better care of your swimming pools. If I can be of help in any way, I can be reached on my cell phone at (916) 201-7665.