Which chlorine & why?

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.

Which chlorine do you use in your pool?

Trichlor - granules, tabs, pucks
288
39%
Dichlor
71
10%
Cal Hypo
92
12%
Chlorinating liquid
165
22%
Bleach - supermarket style
122
17%
 
Total votes: 738
Guest

Which chlorine & why?

Postby Guest » Mon 24 May, 2010 07:57

Very informative! How much Clorox do I add to raise 10,000 gallons 1 ppm? If I know that I can adjust for pool size and ppm target.

Thanks


chem geek
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Which chlorine & why?

Postby chem geek » Mon 24 May, 2010 12:33

It takes 20.7 fluid ounces (about 2.6 cups) of 6% Clorox Regular unscented bleach (6.17% Trade; 5.71% Available Chlorine) in 10,000 gallons to raise the Free Chlorine (FC) level by 1 ppm. You can use The Pool Calculator to calculate dosages for many chemicals and water parameters.
floridapooltech
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Which chlorine & why?

Postby floridapooltech » Mon 24 May, 2010 20:41

chem geek wrote:
One can operate with Trichlor tabs/pucks and high CYA levels if one pays extra for algaecides or phosphate removers and/or shocks weekly, but this is all extra cost. In fact, when one accounts for the cost of pH adjustment when using Trichlor, it isn't always less expensive than chlorinating liquid or bleach on a per FC basis.

Richard


Chem Geek-

You refer to the use of a phosphate remover as if it were related to CYA levels. This is very untrue. Phosphates are introduced into a swimming pool from fertilizer, areas close to phosphate mines (mainly florida), rain and seawater (then jumping into your pool afterward). Phosphates are algae "food", and therefore have NOTHING to do with CYA. As for algaecides, I use tri-chlor pucks in my own pool, without the need for algaecides. No matter what form of chlorine you use, you will have to superchlorinate using a shock, liquid, etc...This will raise your FC. Stating that the use of tri-chlor tablets will lead to the requirement of expensive phosphate removers, algaecides, flocculants, weekly shocking etc....is false!
czechmate
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Which chlorine & why?

Postby czechmate » Mon 24 May, 2010 22:19

Dear Swimsnaveusa,
Richard has a 1600 inputs mainly water chemistry related. I would venture to say that myself, I never seen him to be of target with his response.
You have to know little more about cross referencing and read between lines to understand, what he refers to.
At CYA 80, just to ward off algae start, you have to maintain FC close to 8ppm. It is expensive and not really healthy to swim in. That is where the starving of potential algae has its true benefit and importance, since even high chlorine presence may not give you needed protection. That starving is achieved by removing phosphates from the water.
Also, believe me, there is a lot more sources of phosphates than you listed here.
Just couple of weeks ago I stopped treating my pool against phosphates coming from pecan pollen. It was totally invisible in the pool water. When I washed patio every morning, the wash-off of was greenish yellow.
We all recognize the phosphates in decaying leaves but the pollen is often invisible culprit, where Phosfree bi-weekly maintenance pays off.
Further, you do not have to superchlorinate on regular basis, as long as you will maintain required level of FC dictated by the CYA level. Only storms and out of ordinary events introducing debris or or organic mater to your pool may require shocking.
To me, removing phosphates is a lot cheaper than trying yo kill established algae with algecides and chlorine shock at 30% CYA.
chem geek
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Which chlorine & why?

Postby chem geek » Tue 25 May, 2010 01:15

swimnsaveusa wrote:Chem Geek-

You refer to the use of a phosphate remover as if it were related to CYA levels. This is very untrue. Phosphates are introduced into a swimming pool from fertilizer, areas close to phosphate mines (mainly florida), rain and seawater (then jumping into your pool afterward). Phosphates are algae "food", and therefore have NOTHING to do with CYA. As for algaecides, I use tri-chlor pucks in my own pool, without the need for algaecides. No matter what form of chlorine you use, you will have to superchlorinate using a shock, liquid, etc...This will raise your FC. Stating that the use of tri-chlor tablets will lead to the requirement of expensive phosphate removers, algaecides, flocculants, weekly shocking etc....is false!

I'm sorry if my post implied the connections that you have referred to. Let me spell this out more clearly. The connection is indirect, not direct.

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases the Cyanuric Acid (CYA) level by 6 ppm. That is a chemical fact. Even at a low 1 ppm FC per day chlorine usage, this is an increase of over 100 ppm CYA in 6 months if there is no water dilution. This is also a fact and happened in my own pool 7 years ago when I was using Trichlor and happens in pool after pool reported on multiple pool forums (including this one). In my pool, it took about 10 months over 1-1/2 swim seasons at around 0.8 ppm FC per day to go from 30 ppm to over 150 ppm CYA -- I have a cartridge filter so no backwashing and there are no summer rains and I had a pool cover pump for the winter on my electric safety cover so essentially minimal dilution of the pool water. Even though I was using a PolyQuat algaecide, though only every other week, after I got to 150 ppm CYA the chlorine demand in my pool shot up and it was harder and harder to keep up with chlorine demand until eventually the water started to turn dull and then cloudy as algae grew more and more quickly. That's when I decided to learn pool water chemistry to figure out what was going on in my pool and quickly learned about the chlorine/CYA relationship (from both scientific literature and from The PoolForum.

Higher CYA levels require proportionately higher FC levels to have the same active chlorine (hypochlorous acid) level. This is also a chemical fact known since at least 1974 as determined from the equilibrium constants in this scientific paper and that describe in further detail in this post. It is the hypochlorous acid that is largely responsible for disinfection, oxidation and prevention of algae growth. So as the CYA level climbs from continued use of stabilized chlorine products, the FC must be proportionately raised if one is to prevent algae growth without the use of supplements (unless one is lucky with nutrient-poor water).

Algae are plants and need water, sunlight, a source of carbon (such as carbonates and carbon dioxide), a source of nitrogen (such as nitrates or for some cyanobacteria aka blue-green algae, nitrogen gas), and a source of phosphorous (such as orthophosphate or, more slowly taken in, simple organic phosphates). Algae growth is also dependent on temperature.

So there is a race between algae growth which is limited by the above factors vs. the rate of killing by chlorine which is based mostly on the hypochlorous acid concentration which in turn is proportional to the FC/CYA ratio. Even with all of the phosphate and nitrate nutrients that algae could possibly utilize, their growth is still ultimately limited by sunlight and temperature where algae doubles in population in 3 to 8 hours depending on species. Therefore, chlorine is able to kill algae faster than it can reproduce if the FC/CYA ratio is high enough. For almost all green algae found in pools, having the FC be at least 4.5% of the CYA level kills the algae faster than it can grow and is suitable as a minimum chlorine level for saltwater chlorine generator (SWG) pools. In manually dosed pools, the recommendation is usually 7.5% of the CYA level.

If one does not maintain the minimum FC/CYA ratio (including cheating if one shocks regularly), then one can supplement the chlorine in preventing algae growth by either using an algaecide (PolyQuat 60, copper ions, 50 ppm borates, etc.) or use a phosphate remover to slow down algae growth. If one happens to have a pool poor in phosphates, then obviously the phosphate remover isn't necessary.

If one maintains chlorine at the appropriate FC/CYA levels, then there is no need for shocking the pool. The chlorine is able to keep up with oxidizing bather waste, killing pathogens, and preventing algae growth continually so there is no need to raise the FC on a regular basis. See this thread to see that the tens of thousands of pool users at The PoolForum and Trouble Free Pool do not need to shock their pools except for infrequent circumstances such as pool openings, dead animals, etc. Why do you believe that shocking a pool to raise the FC is necessary?

As for your own pool, you are fortunate that your continued use of Trichlor has not led to unusually high chlorine demand or algae growth. Your regular shocking helps make up for the low FC/CYA ratio and you may have more water dilution in your pool from backwashing or rain overflow that keeps your CYA from rising too quickly. Your pool might be naturally low in algae nutrients including nitrates or phosphates. You might even be using Trichlor that has copper in it (some does). My fill water contains 400 ppb phosphates and my pool has had 2000-3000 ppb phosphates yet did not get algae (after that first year) so long as I kept the proper FC/CYA ratio just as the tens of thousands of residential pool owners have done.

The pool store where I buy my chlorinating liquid also services thousands of pools (they have many trucks and personnel) and they make sure the CYA level doesn't get above 100 ppm and they keep a minimum 4.5 ppm FC level in those pools. I asked them why and they said it was to prevent algae growth, that the manufacturers told them there was no problem to 200 ppm CYA, but the pool store folks said that simply wasn't true in their experience. They also found that the 1-3 ppm FC recommendation from BioGuard and the 1-1.5 ppm recommendation from GLB were woefully inadequate at the higher CYA levels.

But most importantly, it is the tens of thousands of pool owners that have validated that chlorine alone can be used to prevent algae with no need for regular shocking or supplemental products and also having a stable pH (which cannot be said for Trichlor which requires pH raising products since it is so acidic). The most common reason by far for algae problems reported on multiple pool forums is from too low an FC/CYA ratio which usually comes about from continued use of stabilized chlorine products (Trichlor and Dichlor) that continually raise the CYA level. When the science is there and people's experience validates it on a large scale, it seems pretty solid to me.

Trichlor ---> CYA increases ---> FC/CYA decreases ---> HOCl decreases ---> Algae grows faster than chlorine can kill it
Phosphate Remover ---> Phosphates decrease ---> Algae grows slower so lower chlorine can kill it

Richard
brianVLX

Which chlorine & why?

Postby brianVLX » Fri 28 May, 2010 22:58

I'm wanting to switch from Trichlor to Liquid Chlorine. I have a 30,000gal above ground pool. How do I determine how much liquid chlorine to dump in? And do I do this daily?? Any tips or info would be appreciated!

thanks,
Brian
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Which chlorine & why?

Postby chem geek » Sat 29 May, 2010 02:07

You can use The Pool Calculator to calculate dosages. If you don't use a partially opaque (say, blue as opposed to clear) pool cover, then you will need to add chlorine every day or two. I have a mostly opaque cover and add it twice a week. You can add it less frequently if you have more chlorine swings or you can automate chlorine dosing using The Liquidator or a peristaltic pump or a saltwater chlorine generator.

You can use the Trichlor tabs/pucks when you go on vacation (for about a week) and can use them occasionally if your CYA gets low from water dilution. You can use Cal-Hypo when you want to raise your Calcium Hardness (CH). Read the Pool School for more info on how to maintain your pool.

A 30,000 gallon pool is rather large so the chlorine quantities will be high unless you use a pool cover that is at least partially opaque to the UV rays in sunlight. You can reduce chlorine loss from sunlight with a higher CYA level, but that gets risky if the FC gets low. The main point is to learn about your options and the effects of different chlorine sources and figure out what works best for you.
brianvlx

Which chlorine & why?

Postby brianvlx » Sat 29 May, 2010 18:57

Thanks for the input! Here is another for you....what's your opinion on "The Liquidator"???? I've tried to search for some reviews, etc...but haven't found much useful info other than how it works (which i found on the company's website). Do they work? Any issues with them? Costs? Where do you get them?

Any input would be appreciated!!
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Which chlorine & why?

Postby chem geek » Sun 30 May, 2010 02:58

It works for some people but not for everyone. You can read more about it at this thread, this thread and this thread.

There is an upgrade to the tubing in both quality and size (1/2" to 3/8") that is essential and unfortunately you have to do yourself. To minimize the amount of calcium deposits in the output valve, one can use 50 ppm Borates, keep the saturation index slightly negative, and/or use 6% bleach instead of 10%/12.5% chlorinating liquid. However, some of those using the Borates have been able to use chlorinating liquid. Also, get the 8-gallon unit.

The Liquidator is sold here for around $180. You can see an instruction manual here.
PBROWN

Which chlorine & why?

Postby PBROWN » Tue 14 Dec, 2010 10:17

Liquid Chlorine is a great time proven method of sanitization.
There can be complications in hauling, and leaking.
Sticks are kept in an air tight drum which reduces corrosion
in the pump room. Less trouble to haul for the average pool owner.
Plus, they are already stabilized. But Soda Ash will have to be added
on a regular basis for pH balance.

Thanks,
Pat Brown
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Which chlorine & why?

Postby chem geek » Tue 14 Dec, 2010 20:24

The problem with stabilized chlorine is that you can get a significant buildup of Cyanuric Acid (CYA) over time. If you don't have a lot of water dilution, the buildup can be fairly rapid. The following are factual chemical rules 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 7 ppm.

So even with a very low 1 ppm FC per day chlorine usage, after 6 months of Trichlor one adds more than 100 ppm CYA if there is no water dilution.
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Which chlorine & why?

Postby miguelle » Tue 17 Jan, 2012 07:55

I am a new pool owner as far as owning own pool with no pool guy maintaining it anymore. My husband and I live in a hot HUMID climate. Shock packets were costing us a fortune last summer. Our pool gets heavy usage from kids and their friends. Our pool unfortunately is surrounded with many trees so algae from leaf droppings was a huge problem. Also, our pool has a blue bottom so shock granuels were always sinking to the bottom of the pool leaving a white sand film. The pool never looked totally maintaned or clear for more than a day or 2 and still always had algae. UNTIL one day my husband got fed up and went to the grocery store. He came back with a carload of Clorox liquid bleach and end of story!! I was skeptical until I saw the beautiful crystal clear appearance!! I became a true believer after testing the chemical levels twice daily and ph fine along with chlorine levels fine everyday!! Even after swimmers. We will never go back to shock powder. We do however still keep chlorine tablets floating in the floater at all times. This is the only time we visit our local pool store!
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Which chlorine & why?

Postby chem geek » Wed 18 Jan, 2012 11:11

Just note that you don't want to use ONLY chlorinating liquid or bleach (or Cal-Hypo or other unstabilized chlorine) if you don't have any Cyanuric Acid (CYA) in the water. You want some CYA in the water not only to protect chlorine from breakdown from the UV in sunlight, but also to moderate chlorine's strength. Otherwise, it will be far too harsh on skin, swimsuits and hair. Read the Pool School for more info including the Chlorine / CYA Chart to know how much chlorine relative to CYA that you need to prevent algae growth (roughly an FC that is a minimum of 7.5% of the CYA level).
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Which chlorine & why?

Postby czechmate » Fri 27 Jan, 2012 19:02

Leslie's in Dallas have a 75% Calcium Hypochloride in a 100# bucket for under 150 dollars. By pound it is 4.99 most places. It is not the only stuff you want to use, but the savings will buy plenty other chemicals!
It should be the same price down in your area.
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Which chlorine & why?

Postby lucy brightley » Tue 20 Mar, 2012 06:35

Chlorine or Bromine? We've put together a helpful article that looks at the difference between these two pool sanitisers and which one is best for your pool.http://yourpool.co/running/chlorine-or-bromine/

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