Green Algae Gone

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
Rauscher's Pool Care

Green Algae Gone

Postby Rauscher's Pool Care » Wed 21 Jul, 2010 13:53

In my 10 years of experience, the only way to guarantee that the green algae stays gone is to have weekly, professional care by a good pool technician. It has taken me years to be able to guarantee my customers they will not see any green algae with my weekly full service.

To see a full listing of what a full service visit should include please visit my website

click on Services, and go to Monthly Full Service.

These techniques all work together to keep green algae gone for good.

Best of luck,

Rauscher


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Green Algae Gone

Postby chem geek » Wed 21 Jul, 2010 21:14

I'm sure you do a great job for your customers, but it is not true that only professional pool care can guarantee no algae. There are over 20,000 users at The PoolForum and over 15,000 users at Trouble Free Pool plus many more at this and other pool care websites that manage their pools easily and inexpensively using pretty much chlorine alone to prevent algae growth. No algicides, phosphate removers, copper ion systems, clarifiers, flocculants, enzymes, ozone or oxygen oxidation system, or even weekly shocking. All that is needed is to understand the chlorine/CYA relationship and how it affects disinfection, oxidation and algae prevention. You can learn more by reading the Pool School .

When I first got my pool 7 years ago, I started out using Trichlor pucks/tabs in a floating feeder, but after 1-1/2 years I started to get an unusually high chlorine demand and then the water turned dull and then cloudy as an impending algae bloom was developing (the acidic pucks also rusted out some mounts to stainless steel bars below the water line). This was in spite of using an algicide, though only every other week. What I didn't realize was that the continued use of Trichlor was building up Cyanuric Acid (CYA) in the water making the chlorine less effective because I was not proportionately raising the Free Chlorine (FC) level to compensate. I didn't realize the following chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

I have a mostly opaque electric safety cover, minimal summer rains, a cartridge filter, and used a pool cover pump over the winter taking rain water into the drain (not in the pool). So I had minimal water dilution. Even with my low 0.7 ppm FC per day chlorine usage, my pool went from 30 ppm CYA to over 150 ppm CYA in around 11 months of swim season use (roughly 1-1/2 years counting the winter season that used hardly any chlorine). 0.7*30*12*0.6 = 139 ppm so added to the initial 30 minus the small dilution got to 150 ppm. Not a mystery IF you are told the truth.

(more in next post...limit of 5 URLs per post)
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Green Algae Gone

Postby chem geek » Wed 21 Jul, 2010 21:17

(continued from previous post)

Once I went to The PoolForum and found out about the chlorine/CYA relationship empirically determined by Ben Powell and later worked out by me in this spreadsheet , I have used only 12.5% chlorinating liquid from my local pool store that is reasonably priced and where they reuse the bottles (so better than recycling) plus a small amount of acid every month or two. The pool is used more now open every day for 1-2 hours plus longer on weekends so the chlorine demand is around 1 ppm FC per day. This costs me $15 per month in chemicals for my 16,000 gallon pool shown here and here . I add chlorine around twice a week (without the pool cover, I'd need to add it every day or two).

The chlorine/CYA relationship has been known since at least 1974 as described in this scientific peer-reviewed paper . There is a lot of misconception in the pool/spa industry and I write about some of these and improvements that could be made to the CPO course in this thread .

Richard

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