Stabiliser too high?

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
pdiddy
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My Pool: 10m x 5m pool at our France holiday home, with skimmer filtration.
Location: United Kingdom

Stabiliser too high?

Postby pdiddy » Wed 06 Jul, 2011 13:38

:? We have had our swimming pool at our holiday home in France for 12 years, partly maintained for us when our paying guests are in residence by a local person, and by us when we are in residence. For the first time (in 12 years) our 'person' has told us that the stabiliser level is too high, and that he has had to change 1/3 of the water to dilute the stabiliser. This is a shock as we replaced the pool liner (and water) last year, removed 1/3 of the water in the Autumn before winterising and everything was fine at the end of May when we were last there. Surely just using non-stabilised chlorine for a couple of weeks would have solved the problem? Thanks for reading, any advice or views on the stabiliser issue?


chem geek
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Stabiliser too high?

Postby chem geek » Wed 06 Jul, 2011 23:36

The following are 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.

With a typical 2 ppm FC per day chlorine usage, Trichlor pucks/tabs will increase CYA by over 35 ppm PER MONTH if there is no water dilution. Higher CYA levels make chlorine less effective unless you proportionately raise the FC level. This is because the amount of active chlorine (hypochlorous acid) is proportional to the FC/CYA ratio. Read the Pool School for more info.
czechmate
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My Pool: 16 x 32 gunite21000 gal., Diamond Brite Blue, Swimquip XL pump, DE36
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Stabiliser too high?

Postby czechmate » Mon 11 Jul, 2011 22:32

Couple of days ago I had my water tested at Dolphin Pool Suply store here in Dallas. When I was told that my FC at 5.5ppm is too high I replied that it is probably a little low due to the CYA being at 90ppm. The girl doing the testing did not understand the correlation and called over Mr. Bryan, the store well experienced employee.
He explained me, that even at CYA at 200ppm all I need is 3ppm of free chlorine to ward of start of algae and maintain a beatiful pool water.
He also told me, that he is teaching Pool School and know all about the pool water chemistry.
Now, do I have a legitimate reason to maintain level of FC at 7-10% of the CYA, or is there some new development in pool chemistry that I do not know about, that makes this guy's statement correct?
Do I waste all that extra chlorine for no good reason?
chem geek
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Stabiliser too high?

Postby chem geek » Tue 12 Jul, 2011 03:08

There is science and then there is what people believe who have a personal financial interest. The science of the chlorine/CYA relationship has been known definitively since at least 1974 as described in this scientific peer-reviewed paper . You can also look at the many references in the "Chlorine / CYA Relationship" section of this post and you can look at the posts from tens of thousands of pool (and spa) owners at The PoolForum , Trouble Free Pool and here that keep their pools algae free and sanitary using chlorine alone without the need for algaecides, phosphate removers, clarifiers, flocculants, enzymes, or even weekly shocking. Or you can listen to Mr. Bryan. Since Mr. Bryan "know all about the pool water chemistry", perhaps you could show him these scientific references that should enlighten him.

You might be lucky to not have a lot of algae nutrients in your particular pool so if you want to take a chance and lower your FC to 3 ppm and raise your CYA to 100+ ppm, go right ahead, but if you do get algae then I'm sure Mr. Bryan will have all kinds of products to sell to you to "solve" the ensuing problem. If you really want to use a lower FC and don't want to worry about rising CYA, then you can use products at extra cost such as algaecides, copper ions, phosphate removers and also do weekly shocking to boot. This is likely to cost you more, have side effects of staining (from the metal ions, if their levels or the pH get too high), or not work completely as the CYA gets too high. Note that the 7.5% minimum for manually dosed pools has a little safety margin in it -- saltwater chlorine generator pools can usually get as low as an FC that is 5% of the CYA level. Nevertheless, these levels are set to work with pools that even have high phosphate and nitrate levels.

I can tell you for a fact that 3 ppm FC is absolutely, positively not enough to prevent algae growth at high CYA levels since that is the FC level I had in my own pool when I first had it built 8 years ago. I used Trichlor pucks in a floating dispenser and for the first year and a half things were OK, but then I found that I needed to use more Trichlor pucks to keep the chlorine level at 3 ppm and the water then started to turn dull and then cloudy. It was an impending algae bloom! My CYA level had risen from 30 ppm to 150 ppm yet 3 ppm FC was unable to prevent algae growth in spite of my using PolyQuat algaecide, though only every other week. Had I not used algaecide, I probably would have had algae start somewhere in the 50-80 ppm range. On the other hand, if I had used the algaecide weekly, then I perhaps could have gotten to 200-250 ppm CYA before I had a problem.

I have a mostly opaque electric safety cover and at that time the pool was not used every day so the chlorine demand was fairly low at around 0.7 ppm per day (the water was kept warm at around 88ºF). For every 10 ppm FC the Trichlor tabs added 6 ppm CYA. Over 11 months of the 1-1/2 swim seasons (winter used hardly any Trichlor) I had 30 + 0.7*11*30*0.61 = 171 ppm so with some splash out and chlorine oxidation of CYA this ended up at 150 ppm. I have an oversized cartridge filter that only needs cleaning once a year and at that time I pumped winter rains off the cover and into the sewer (i.e. not into the pool) and we don't get summer rains so there was minimal water dilution. This is when I found The PoolForum and PoolSolutions and learned the truth from Ben Powell. I then researched the fundamental chemistry, found the O'Brien paper and many other papers, and realized that the pool industry intentionally keeps chemical facts from the public in order to sell more product. It's not the fault of your dealer -- they only know what the chemical manufacturer sales reps tell them.

I now use only 12.5% chlorinating liquid twice a week in my pool plus a small amount of acid every few weeks. My chlorine demand is now higher at around 1 ppm FC per day since the pool is now used every day and this all costs only $15 per month for my 16,000 gallon pool shown here and here . Most residential pools without pool covers have higher chlorine usage, usually in the 1.5 to 2.5 ppm per day range (sometimes up to 3 ppm, depending on conditions). Note that I have had 3000+ ppb phosphates in the pool at some times yet have kept the pool algae free by using chlorine alone.
czechmate
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My Pool: 16 x 32 gunite21000 gal., Diamond Brite Blue, Swimquip XL pump, DE36
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Stabiliser too high?

Postby czechmate » Tue 12 Jul, 2011 09:14

Richard,
you are truly a gift to this site and I have been admiring your dedication for a couple of years now.
It is not the amount of your contributions to forum, rather the detailed sometimes quite lenghty elaborations, always supported by the hard facts.
Back to the Bryan person, funny you mentioned his prompt remedy if his theory did not quite worked out!
You see, one thing I left out of my conversation with him was the fact, that I was trying to avoid buying those 3 bottles of algecide he just sold to the old gentleman at the cost of 33.99 per bottle!
Good day to you and thanks for your input!!
petershobasky
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Stabiliser too high?

Postby petershobasky » Thu 24 Nov, 2011 03:29

pdiddy wrote::? We have had our swimming pool at our holiday home in France for 12 years, partly maintained for us when our paying guests are in residence by a local person, and by us when we are in residence. For the first time (in 12 years) our 'person' has told us that the stabiliser level is too high, and that he has had to change 1/3 of the water to dilute the stabiliser. This is a shock as we replaced the pool liner (and water) last year, removed 1/3 of the water in the Autumn before winterising and everything was fine at the end of May when we were last there. Surely just using non-stabilised chlorine for a couple of weeks would have solved the problem? Thanks for reading, any advice or views on the stabiliser issue?


Hi There!
I have also purchase a new Swim spa from a Canadian Spa Company. It is working fine till now but i am wanted to purchase a new pool can you suggest me from where i can purchase the best and affordable pool.

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