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Thread: 5 reasons to use a Salt-Water Chlorination (SWC) system

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    5 reasons to use a Salt-Water Chlorination (SWC) system

    This article was published in an industry magazine, about 6-7 months ago, something for people to read

    Five reasons to use a Salt-Water Chlorination (SWC) system on a swimming pool.

    Over recent years Salt Water Chlorination (SWC) has gained favour as a safe, reliable and economic method of disinfection. It is well suited to the treatment of swimming pools. While the capital cost may be a consideration, the significantly lower operating cost and high level of safety means SWC is appropriate in many instances.
    Traditionally the preferred method of disinfection of swimming pools was chlorine in liquid or tablet form. Although this method is very effective, the risk of transporting and handling such a dangerous chemical has meant many chlorine-dosing systems were phased out in favour of alternate systems such as Salt Water Chlorinators.
    Saltwater chlorination is a process of sanitising water, using chlorine that is produced in the pool water from ordinary salt. Developed in Australia over 30 years ago, the technology is utilised in over 90% of all residential pools in Australia today. The process occurs via electrolysis, using ordinary salt and a device called a saltwater chlorinator - also referred to as a chlorine generator, salt chlorine generator, or salt chlorinator. Initially, a certain amount of salt is added to the water. As water passes over the chlorinator's specially coated plates, an electric current breaks down the salt and water into their basic elements to form sodium hypochlorite, which is the active sanitizer in all forms of chlorine. The chlorine kills algae and bacteria in the water and oxidizes the waste. Thereafter, the chlorine regenerates itself back to salt and begins the process over again in a virtually unending cycle. Since salt does not evaporate, an occasional addition of salt is needed only to replace what is lost due to the splash out, pumping out, draining or backwashing.

    Reason 1 – Economical

    The obvious advantage is the cost effectiveness of the salt-water chlorination system. Imagine you spend $15 per day currently on chlorine, over a period of five years you will spend in excess of $25000. An equivalent SWC System will cost around 1/10th of that amount, with running costs being equal to 1/5th. The system would pay for itself in less than one year.
    Aside from the initial start-up, salt is only added to replace what is lost due to splash out, backwashing, pump out or draining, making the additional salt expense very small. And, depending on climate and usage conditions, cells can last up to 5 years, and can be replaced.

    Reason 2 - Safe

    A salt-water chlorinator makes chlorine in the pool water, automatically and continuously, so you no longer have to buy, store or handle the dangerous chemical liquid chlorine. Personal injury risks associated with the storage of chlorine are eliminated, as are the other risks of potentially harmful situations where accidental contact with these dangerous chemicals by pool visitors or maintenance staff can occur. When using SWC equipment failures no longer represent a life threatening situation or a potential health risk.

    Reason 3 – Bather satisfaction

    Our studies show that over 95% of swimmers prefer swimming in salt-water pools to any other type of sanitised pools. Salt has a softening effect, just like a water softener, so hair and skin feels soft and silky rather than dry and brittle as with packaged chlorine. The other very important factor is that when the water flows through the electrodes, the chloramines (“dead chlorine” that causes the strong chlorine smell and stinging eyes) are destroyed thus leaving the water in pristine condition.
    Salt-water pools are popular because most people who consider themselves "sensitive" or "allergic" to chlorine are not actually reacting to the chlorine at all. This problem usually arises from use of packaged pool chemicals due to additives contained in those chemicals. The same swimmers, who claim allergic reactions to chlorine, typically experience no problems when they are in a salt-water pool. The answer isn't the absence of chlorine. Salt systems generate their own chlorine on-site. The answer is the absence of all the packaged chemicals and by-products of those chemicals.

    Reason 4 – Environmentally friendly

    Salt is a safe and naturally occurring element. A salt-water chlorinator recycles the salt over and over so there are no by-product wastes added to the environment. Due to high efficiency of the technologies used, on-site chlorine generation requires a far less energy consumption when compared to the commercial chlorine plants. Reduced handling of chlorine means less environmental damage due to accidental spillages.
    Some salt-water chlorination systems also allow for the use of seawater in swimming pools. This kills two birds – allows preservation of fresh water for where it is needed more and reduces running costs further because there is no need to buy salt. Potential water savings from usage of seawater are enormous.

    Reason 5 – Reduced maintenance


    The only maintenance required with salt-water pools, apart from maintaining water chemical balance is periodical cleaning of the cell electrodes. Some SWC systems come standard with ‘self-cleaning’ capabilities to further lessen the burden of maintenance. This means the chlorinator will reverse the polarity of the electrodes periodically in order to reduce the build up of calcium deposits on the cells. Keeping the cells clean will ensure the cells always perform at their peak.


    Salt-water pools used to be the exception, now they are becoming a widely accepted method of water treatment in swimming pools. Majority of builders now make salt water systems standard on their new pools. When considering the opportunity to replace the outdated methods of dosing a pool with dangerous chemicals, the safety factors alone are enough reason to upgrade. Though it is usually the realisation that salt-water sanitation is by far the most economical method of pool sanitation that prompts owners to upgrade.

    Written by Taras Didenko,
    © Australian Innovative Systems Pty Ltd
    http://www.autochlor.com.au/

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    Administrator JasonLion's Avatar
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    Good reading! Thanks for sharing.

    I take slight exception to the economical section. Calculations done over at Pool Forum showed a SWG at best breaking even compared to chlorine from bleach and usually costing slightly more. I would replace this section with connivence. A SWG reduces (not eliminates) the frequency of testing and adding of chemicals, and eliminates the routine purchasing and transportation of chlorine.
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    Senior Member ktdave's Avatar
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    Excellent article Strannik! Thanks for sharing! I'm only 6 months into the use of my SWC system, but I can say that it (as well as TFP!) has really made maintaining my chlorine VERY EASY!
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    Senior Member No P in my ool's Avatar
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    Quote Originally Posted by JasonLion
    Good reading! Thanks for sharing.

    I take slight exception to the economical section. Calculations done over at Pool Forum showed a SWG at best breaking even compared to chlorine from bleach and usually costing slightly more. I would replace this section with connivence. A SWG reduces (not eliminates) the frequency of testing and adding of chemicals, and eliminates the routine purchasing and transportation of chlorine.
    I have to agree with this statement. They really are a convenience thing.
    21' Leslies Beachland Ag Pool, 10,000 gallons, professionally installed (best money I ever spent) Hayward 16" sand filter w/Pentair two speed pump Fafco 4x20 solar heater,Aqua Trol RJ. Borates added. Hard plumbed.

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    Now you have my curiosity up. I'm going to have to read up in the forum about salt water, Saturday night.

    I have more questions floating thru my head then brain cells.
    Hotrod30

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    This article was published in australian magazine for motel owners, with pools generally being 100000-150000 litres.

    For Australia and for AutoChlor chlorinators section 1 is true. Sodium Hypochlorite which is the most common type of chlorine used here, costs around $1/litre. With chlorinator, equivalent will cost you ~13c in electricity. So you save around 80c on every litre of your chlorine. With chlorinator producing 30g/h(equiv. of 240gm/h of sodium hypochlorite) retailing at around $1500 you only need to put around 1800 litres of sodium hypochlorite in your pool to break even.

    If somebody gives me a price of bleach, chlorine concentration in it and cost of electricity, i'll be happy to recalculate for US conditions.

    Of course if you get chlorinators with all the bells and whistles, than your savings will be minimal if any.

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    Senior Member JCJR's Avatar
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    At first I wanted a SWG, but after reading all the pro and cons I think CL is the best way for me to go.

    $15 a day for CL? Sorry but I use probably $1 a day for 9 month and $.50 the other 3 months and I have a large residential pool by most standards.

    My neighbors dog chewed on of the sensor cables and he said it costs about $100 to replace, so there are other costs as well. Not to mention he has been using Liquid CL while he orered the part. The story does not go into the electrical cost of operating a SWG.

    Convenience a SWG is better but I only go the pool store 2x a months to by CL now that I have the Liquidator ( I sound like I own stock ).

    If the cells come down in price and Liquid Bleach goes up, then I will probably change my mind.
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    Quote Originally Posted by Strannik
    This article was published in australian magazine for motel owners, with pools generally being 100000-150000 litres.

    For Australia and for AutoChlor chlorinators section 1 is true. Sodium Hypochlorite which is the most common type of chlorine used here, costs around $1/litre. With chlorinator, equivalent will cost you ~13c in electricity. So you save around 80c on every litre of your chlorine. With chlorinator producing 30g/h(equiv. of 240gm/h of sodium hypochlorite) retailing at around $1500 you only need to put around 1800 litres of sodium hypochlorite in your pool to break even.

    If somebody gives me a price of bleach, chlorine concentration in it and cost of electricity, i'll be happy to recalculate for US conditions.

    Of course if you get chlorinators with all the bells and whistles, than your savings will be minimal if any.
    Bleach price varies widely across the US, depending primarily upon distance from the bleach plant and how far the bleach plant is from a port to get caustic and gas.

    Here, in Houston TX our prices are cheap. A commercial facility could expect to pay roughly .99 -1.29 per gallon for bulk deliveries of 10.5% bleach (bulk being 100 gallons plus). Electricity ranges from .09-.15 per kw hour.
    21' Leslies Beachland Ag Pool, 10,000 gallons, professionally installed (best money I ever spent) Hayward 16" sand filter w/Pentair two speed pump Fafco 4x20 solar heater,Aqua Trol RJ. Borates added. Hard plumbed.

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    Ok so in your case we get:

    Chlorinator producing 30g/h of pure chlorine - equv. of 285 g of 10.5 bleach.
    Under worst condition it will use 0.3kWt/h.

    To make 1 gallon of bleach equiv, you will need to run chlorinator for 13 hours.

    So the price of gallon becomes:
    0.3*13*0.15 = $0.585 - worst case scenario (Saving 0.99 - 0.59 = 40c)
    0.3*13*0.9 = $0.35 - best case scenario ( Saving 1.29 - 0.35 = 94c)

    That still gives you 40% saving assuming maximum electricity costs and minimum bleach price.

    With chlorinator costing say $750 and you having to put 1 gallon of bleach a day, it will take ~ 5 years to break even.
    With 5 years generally being the life of a cell your saving will start after 7.8 years (assuming costs of new cell after 5 years @ $530.)

    Now in the best case scenario you break even after 2 years of use, with savings over remaining 3 years being $960

    Again, each new cell will pay for itself after 1.4 years.

    Also if you don't buy it in bulk, which i imagine having a small pool you generally wouldn't (correct me if i'm wrong here), your price of bleach goes up, consequently you save even more.

    The bigger your pool is - the more you save, as bigger chlorinators are more energy efficient.

    So to say that chlorinators are more expensive than using bleach is not correct. They are at least the same costs in the worst case scenario. But usually you will save.

    If anyone sees mistake in my calculations, or has their own - please feel free to post up.

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    Calculation for commercial facility

    Cost of chlorinator producing 200 grams/hour: $12 800 (includes $1000 freight costs)

    Energy consumption: 1kWt.

    200g = 1.9 kg of equiv. bleach
    You would need to run your chlorinator for 2 hours a day to make a gallon:
    2*0.15 = 30c/gallon (Saving of 70c/gallon in worst case scenario)
    2*0.09 = 18c/gallon (Saving of 1.07c/gallon in best case scenario)

    Assuming you run your chlorinator 23 hours a day(allowing 1h for various maintenance), your savings are:
    $8.00 or $12.00/day respectively.

    So it takes 2.9 - 4.4 years to break even. Savings of $1800 - $9100.

    Now a new cell for this chlorinator retails for around $5300.

    So for the new electrode you would have 1.2 - 1.8 years to break even. Savings of $9300 - $16600.

    Now in commercial pools you don't usually dispense bleach manually, you use automatic feeders. Subtract the cost of a feeder from the cost of chlorinator and you get even bigger savings.

    Anyone still considers bleach to be cheaper?

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    Electric rates is several areas are higher than 15 cents/Kwh, particularly in the summer. You also need to consider the cost of acid, since most pools with a SWG will experience steady PH increases. Then factor in that you could be earning 5% to 8% on the money invested in the SWG, so there is a lost opportunity cost there.

    On the other hand, most of us are paying much more than that for bleach. I believe that $0.99 for 96 oz of 6% (5.75% trade) is thought of as a really good price for retail customers. And that is ignoring any taxes and assuming that transporting the bleach is free.
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    Quote Originally Posted by JasonLion
    Electric rates is several areas are higher than 15 cents/Kwh, particularly in the summer. You also need to consider the cost of acid, since most pools with a SWG will experience steady PH increases. Then factor in that you could be earning 5% to 8% on the money invested in the SWG, so there is a lost opportunity cost there.

    On the other hand, most of us are paying much more than that for bleach. I believe that $0.99 for 96 oz of 6% (5.75% trade) is thought of as a really good price for retail customers. And that is ignoring any taxes and assuming that transporting the bleach is free.
    Is it after you count in inflation or before?

    Lost opportunity will cost you around $200/5 years on a 30g/h chlorinator.

    But if you say bleach costs are double what i used in my calculations than savings will be much higher.

    If there is a significant demand, i can knock up a calculator and put it on the web, to calculate savings given different prices of bleach/electricity. Still given all of the info it will at least break even.

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    Well, I briefly read the article at the top when this was first posted and paid little attention but I'm feeling a little cantankerous tonight so here goes:

    1. I do not have an SWG

    2. I might get one

    3. I think all of you that own one are at least as smart as me.......probably smarter.

    4. I think the article above is a bunch of over-hyped half-truths. After reading that, I felt like someone was trying REALLY hard to sell me something I MAY not need.

    a. economical? not in the US

    b. safe? Sure. So is Clorox. That's why you can buy it at the Grocery store right along side the food you eat.

    c. bather satisfaction? Hmmm. Maybe. Most bathers were fairly satisfied before SWG's and the bathers in my pool indicate they are satisfied as well....at least to my face.

    d. environmentally friendly? I was okay with this one 'til he recommended sea water. Ya'll ever swum in the ocean and let the salt dry on you? It ain't a happy feeling!!

    e. reduced maintenance? This one made the most sense to me until I reread the forum for the past year and see all the questions about warning lights, low salt lights, etc. To my knowledge the forum has no posts about problematic Clorox bottles.


    So, please keep in mind #2 above. I may just get one but it won't be for any of the reasons above. I'm just saying I get a little uncomfortable when someone overreaches to sell me something.

    I think JCJR makes a good argument for Clorox. Besides, you SWG guys never get to experience that look you get at the checkout at Wal-Mart with 36 gallons of bleach......now THAT's a real treat!!
    Dave S.
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    Quote Originally Posted by duraleigh

    a. economical? not in the US
    Care to go over my calculations for US conditions above? Or post up your own for that matter?

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    Well, here's a rough "cipher" us good ole' boys in the South do:

    Front money for an SWG big enough for a 42K pool....somewhere about $1500-$2000.

    That's about 1500 gallons of bleach. I use about 150 gallons of bleach annually.

    That's about a ten year supply of bleach and I never get any further than that in the calculations.
    Dave S.
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    Quote Originally Posted by duraleigh
    Well, here's a rough "cipher" us good ole' boys in the South do:

    Front money for an SWG big enough for a 42K pool....somewhere about $1500-$2000.

    That's about 1500 gallons of bleach. I use about 150 gallons of bleach annually.

    That's about a ten year supply of bleach and I never get any further than that in the calculations.
    Assuming you use 150 gallons of 10.5% bleach a year, you need a 20g/h chlorinator with running time of 8 hours/day

    Now i don't know where you buy your chlorinators, but that's a place i would steer away from cause they charge you 3 times the price.

    EDIT:

    I've checked the concentrations for Clorex - it's 6.0% for regular, and 2.75% for scented

    So effectively you would need a chlorinator making ~10 g/h in first case and 5g/h if you use scented.

    If anyone makes you pay 1500 for that - he's clearly ripping you off.

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    Hey guys,

    Though I'm very new to pools and am just a baby in term of knowledge but I can't help chipping in.

    Strannik, I personally think you should knock up a cost calculator for SWG Vs Bleach. I started on SWG (only 2 months ago) but after doing much reading from this site, I've stocked up on bleach too. Electricity here are cheap US0.10/kwh) and bleach in 10% at UDS16.6/6.6gal drum (including drum) delivered. But my cell, I can only get from Australia. Thus, I'll be very interested in your proposed calculator.

    Cheers.

    Vincent.
    8,000 gal IG concrete & tiled lap pool, 1/2 hp pump, 24" sand filter, SWG Auto Clean, whole pool under shed, 3 X 2ft waterfall one end overflow the other end. TF100 Testkit. 80 F Water whole year round.

  18. #18
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    Quote Originally Posted by Strannik
    Ok so in your case we get:

    Chlorinator producing 30g/h of pure chlorine - equv. of 285 g of 10.5 bleach.
    Under worst condition it will use 0.3kWt/h.

    To make 1 gallon of bleach equiv, you will need to run chlorinator for 13 hours.

    So the price of gallon becomes:
    0.3*13*0.15 = $0.585 - worst case scenario (Saving 0.99 - 0.59 = 40c)
    0.3*13*0.9 = $0.35 - best case scenario ( Saving 1.29 - 0.35 = 94c)

    That still gives you 40% saving assuming maximum electricity costs and minimum bleach price.

    With chlorinator costing say $750 and you having to put 1 gallon of bleach a day, it will take ~ 5 years to break even.
    With 5 years generally being the life of a cell your saving will start after 7.8 years (assuming costs of new cell after 5 years @ $530.)

    Now in the best case scenario you break even after 2 years of use, with savings over remaining 3 years being $960

    Again, each new cell will pay for itself after 1.4 years.

    Also if you don't buy it in bulk, which i imagine having a small pool you generally wouldn't (correct me if i'm wrong here), your price of bleach goes up, consequently you save even more.

    The bigger your pool is - the more you save, as bigger chlorinators are more energy efficient.

    So to say that chlorinators are more expensive than using bleach is not correct. They are at least the same costs in the worst case scenario. But usually you will save.

    If anyone sees mistake in my calculations, or has their own - please feel free to post up.

    How much does it change the equation if I regulalry have big 'ol pool parties in July and I need to get 1 gallon of bleach in the pool within an hour? Do I have to wait 13 hours? <g>
    21' Leslies Beachland Ag Pool, 10,000 gallons, professionally installed (best money I ever spent) Hayward 16" sand filter w/Pentair two speed pump Fafco 4x20 solar heater,Aqua Trol RJ. Borates added. Hard plumbed.

  19. #19
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    Quote Originally Posted by Aquaman95
    How much does it change the equation if I regulalry have big 'ol pool parties in July and I need to get 1 gallon of bleach in the pool within an hour? Do I have to wait 13 hours? <g>
    First point to note - purpose of chlorinators is not to shock pools, but to maintain a required level of chlorine over time.

    So in your case i would dump a gallon of bleach when needed and subtract the 0.40c from total savings.
    Essentially if you have party every day for a month, you will need to subtract $12 from the savings amount.

    13 hours was in my calculation because i chose to base all calculations on 30g/h chlorinator

    In reality you'd need something a bit bigger for that pool, so you don't have to run it for 13 hours. General standard we use over here is 8 hours running time. If you have to run it for longer - means your chlorinator is not sized correctly and you are paying unnecessary electricity costs for the pump plus putting strain on your electrodes.

    Now bigger chlorinator will be more energy efficient and will run for less time. Of course capital cost will be higher as well.

    Since there is clearly huge misunderstanding about costs involved in owning a chlorinator vs bleach, i will knock up a calculator in a few days so everyone can calculate according to their condition.

  20. #20
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    I think we've all been known to pay big bucks for some modern conveniences. We pay hundreds a month in the summer to cool our houses, running the dishwasher, clothes washer, clothes dryer. Why not wash the clothes by hand and hang them out to dry? We can get a $12 pizza delivered to our door because we are too lazy to pick it up. So, why go lug bottles of chlorine in your giant SUV and have to dump them into the pool at scheduled intervals when it can all be done automatically for a negligible fee? My time and my back are work something to me.

    It's a convenience and I love it!

    Also, I wouldn't regard Chlorine as safe when it's loaded in a truck or train car when it wrecks. Also, from what I see, there is a gallon to gallon comparison above when a SWG pool can operate at a lower chlorine level.

    my 2c.
    21k gal SW, IG Gunite PebbleSheen, 1HP Jandy, Jandy 340 filter, Polaris 280, 17' fiberglass slide w/ 2HP pump.

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