Problem solving swimming pool algae in August
About the middle of August of this year (2017), I began having real trouble with algae growing in my swimming pool. Since my natural enzymes have worked superbly to keep my pool clean for 2.5 years, I was surprised. I tried
- scrubbing more often and thoroughly
- backwashing the pool extra
- making extra sure the pH was in the correct range
- keeping the cover on more in case too much sunlight was the problem.
Finally, I contacted the nice people at Water’s Choice, where I buy my natural enzymes.
Phosphates and where they come from
Tom Vaughn, co-owner of Water’s Choice with his wife Debbie, gives excellent best customer service. He not only called me back right away, but he knew what to test and what to do with the results. Since there has been heavy smoke in the air from wild fires, the swimming pool water had probably absorbed phosphates from the smoke.
How does that happen? The fires burn lots of organic matter, which has phosphates in it. This releases phosphates into the air. To top it off, phosphates are a main ingredient in fire retardants. Stuff in the air, like phosphates in this case, gets absorbed into the water. Algae likes to eat phosphates. When algae has food, it grow and multiples.
Treating algae growth with phosphate remover and a touch of chlorine
Fortunately for me, I live just 30 minutes from Water’s Choice. Instead of having to wait 2-3 days for something to arrive in the mail, I drove over there the next day and they did the phosphate test for me. My water phosphate levels were between 500 – 1000. That was on the HIGH end of the scale. If phosphates had not shown up as high, he had two other tests in mind, but this was clear results.
There were two main things I needed to do to my swimming pool now:
- add phosphate remover to the water
- shock the water with about 3 tablespoons of chlorine granules (for my 4000 gallon pool)
The first day, I was to add one ounce (by weight) of phosphate remover. The pool filter was set to “bypass to pool” for 24 hours so that the remover would stay concentrated in the swimming pool water. At basically the same time, I added the chlorine granules. The next day, I set the filter back to normal. (click on any photo to enlarge)

I also swam the next day and was so pleased to see the algae was gone! It was not only gone from the smooth sides of the vinyl liner, it was gone from the nooks and crannies of the ladder and the current generator. The water was barely cloudy, supposedly from the phosphate remover binding with the phosphates. After the filter was run for a day, it cleared up.
Follow-up
Life being what it is, I didn’t get around to testing the phosphates again after 48 hours, like I had been advised to. I did however test it 5 days later. Since the smoke from wild fires had increased dramatically over the last few days, I wasn’t surprised that the phosphates measured as between 300-500. I had looked at the colors during the first test, so I did have some comparison experience to help me evaluate what I was seeing.
Mr. Vaughn had recommended I purchase 2 ounces of phosphate remover since my phosphates had been so high to begin with, so I began the cycle of treatment again. The algae were only just beginning to grow this time, and the results were just as dramatic. The pool was clean again.
With the air still quite heavy with smoke, I expect I may have to do this at least one more time. But at least I now know what the problem is. If you would like to post this information somewhere to help you take care of your swimming pool in the future, click the button below:
Using a bit of chlorine with natural enzymes
I was naturally wary of using any chlorine after my skin issues. Mr. Vaughn pointed out that a couple of tablespoons of chlorine would dissipate quickly. I already knew that the potassium shock I had been using wasn’t making a dent in the algae, so I decided to give it a try. The worst case scenario was that if I had a bit of skin reaction, I would need to stay out of my pool for a day while the chlorine broke down. I am happy to say that I never had any reaction.
Is having a swimming pool worth it?
It is true that problem solving can be a little stressful, especially as a new swimming pool owner. However, I have been able to learn what I need to over these past few years and I am now less intimidated by problems with my swimming pool. I have loved being able to swim year-round, right out my back door, and in a pool that is as clean as I can keep it.