Pool Chlorine Brands – What’s the Difference?

Pool Chlorine Brands - What's the Difference?

Are all pool chlorine brands the same? The short answer is no! While chlorine tablets may look the same across the board, there is usually a big difference in terms of quality and ingredients. Let’s dive into what goes into making a chlorine tablet, and how to pick the best chlorine brand.

Chlorine materials

Materials

Chlorine manufacturing

Manufacturing

Chlorine brand country of origin

Country of Origin

Chlorine Materials

Chemical labeling and MSDS sheets provide a look into the ingredients used in chlorine tablets and pool shock, but manufacturers are allowed “proprietary” license, to not list trade secret ingredients.

Trichlor tablets can contain additives to control algae or improve water clarity. In such cases, a lower percentage of available chlorine will tip you off to the use of fillers or additives. Cheaper binders can gum up chlorinators and cloud pool water. Raw materials can contain impurities or be cut with low grade fillers in cheap chlorine.

Chlorine Manufacturing

How chlorine is made does make a difference in the level of impurities, and in how the chlorine is delivered. Cheaper tableting equipment can produce a crumbly tablet that dissolves too rapidly. A chlorine product’s solubility, hardness and bulk density affects the release rate and is dependent upon the heat and pressure used during tablet formation, as well as the quality and purity of ingredients.

It takes a lot of pressure and heat, and precise cooling to create a well-made chlorine tablet, and do it without harm to the environment. Less sophisticated tableting facilities produce an inferior product and discharge excessive byproducts into air and water.

Country of Origin

In recent years, chemical manufacturers in the U.S. have petitioned the International Trade Commission for protection and sanctions against imported isocyanurate products being dumped on the U.S. market. Late last year, the Dept of Commerce ruled that imported Chinese chlorine was found to be heavily subsidized by the Chinese government, and was unfair to domestic manufacturers.

Differences in Chlorine Brands

In a nutshell, there are significant differences in the quality of chlorine brands. This results in tablets that dissolve too rapidly and leave a gummy residue, and granular products that separate too slowly, and leave behind a cloudy residue.

There are many ways to make a cheap chlorine product, so stick with a major brand; and avoid private label brands and sales on “generic” pool chlorine from big box retailers, home stores or discount clubs, which are domestically packaged with imported chlorine.

No matter what type of chlorine you use — trichlor, dichlor, or cal hypo — look for a respected brand of domestic pool chlorine, and steer clear of chlorine brands of dubious origin or of poor materials and workmanship.

18 thoughts on “Pool Chlorine Brands – What’s the Difference?

  1. David Leone

    try this again..I have a 36 x 16 inground pool. Over the last few years, we have had problems with the steps turning yellowish. Vitamin C take it right off, but it comes right back. We went on vacation, and I forgot to fill the chlorinator. It ran out, but when we returned, the steps were bright white. I added clorine to the chlorinator and put 3 bags of shock into the pool. By the end of the day, the steps began to turn yellow again. Could it be the type of chlorine or shock that we are using? We use a Sams Club brand Chlorine for “All Pools.” Active ingredient, Trichloro-s-triazinetrione = %99. Avaiable Chlorine = %90. Shock is same brand, %99 Sodium Dichloro-s-Triazinetrione Hydrate. My pool store said that is could be due to a metal plate in our electric heater that will cause that in older model heaters (ours is 13 YO). The added chlorine has put doubt to that theory, and made me think that it could be the type of chlorine/shock we use or pool chemistry. I am curious to hear an expert opinion.

    • Hi David, interesting theory, you could stop using the dichlor shock for a while, switch to non-chlorine shock or cal-hypo shock, as needed. Or reduce shocking – or use a sequestering agent regularly. My understanding is that the step discoloration comes from iron, and that shocking a pool that is not treated with a Stain & Scale sequestering agent, can drop-out’ metals and minerals, or knock them out of solution. Any shock will do this actually, not just dichlor. So either stop shocking for awhile, or switch to non-chlorine shock, or treat weekly with a stain and scale.

    • Valerie Xanders

      Did you ever figure this out??? I have been having the EXACT SAME PROBLEM for the past three summers! We even went as far as taking out the heater! They tell me there aren’t any metals in my pool, bit but c takes it away. I thought it was interesting when we opened our pool in the spring… The steps were white after sitting all winter .. as soon as we started shocking and adding chlorine they start turning orange again???!!! I am at my wit’s end… I started thinking maybe it was the same chemicals too??!!

  2. Jaime Pereda

    I live in Arizona where it can get 110+ degrees in the summertime as well as monsoons. What should I be looking for in a chlorine tablet that will get me the biggest bang for my buck. Its hard to trust all these different pool companies that try to push what they sell.

    • Jaime, I would look for a recognizable name, a ‘brand’ that has a lot to lose if they produce poor products. ‘No-name’ brands and imported chlorine specifically, are not made to the same high standards that are mandated by federal law. Trichlor tablets are a very regulated product – I like to make a comparison to Vodka – which also must be made under strict conditions with strict ingredients and processes, to protect consumers from lesser quality. That said – two recognizable brands side by side… I would buy the cheaper chlorine tablet.

  3. Is it better to use the same chlorine for shock and 3″ tablets, i.e. tri or cal…basically is it not a good idea to mix, using different types of chlorine?

    • You can definitely use different types of chlorine, added separately to the water, but different types of chlorine should never touch each other, or be stored in close proximity. Most people use trichlor tabs for everyday chlorination, and cal hypo or dichlor granular for shock treatments or to boost chlorine quickly if tabs run out and (someone) forgot to refill promptly. Also use shock the “A-B-C’s – for removing algae, bacteria, chloramines (and cloudy water).

  4. Should I stay away from chlorine tablets & shock from Home Depot? What about Leslie’s Pool Supply?

    • Hi Connie, Leslies has a good brand of chlorine, and most Home Depots generally do as well. Look for the country of origin, North America is what I like to see. Products that are made overseas are not specifically compliant on the rather strict laws surrounding chlorine manufacturing, including process, ingredients, potency, lifespan, etc. In the US the chemical manufacturing laws are quite tight to protect the consumer, but are not always so in [certain] other parts of the world. Imported products are supposed to meet the same standard, but in my experience, some lesser quality stuff is slipping through…

  5. Jacqueline

    Good evening
    I’m 19 weeks pregnant with my first baby and everything is going swimmingly. I’m looking to go scuba diving next week with my husband in Fiji. We usually go to 20 metres deep and I was wondering how pressure would effect the baby and if it’s safe to scuba dive while pregnant? How deep can I dive?
    Thank you
    Kind regards
    Jacqueline

    • Davy Merino

      Hi Jacqueline, although I am no expert in scuba or the effects on unborn children, there are some reports of problems with hyperbaric oxygen, or oxygen under pressure. Maybe not so much from pressure of being underwater, but from breathing canned air? I found this: “A range of developmental abnormalities have been associated with hyperbaric exposure. These include low birth weights among the offspring of diving mothers 14,15,26; fetal abortion 28; bubbles in the amniotic fluid 13,25; premature delivery 14; abnormal skull development 11,15,16; malformed limbs 11,15,16; abnormal development of the heart 16,20; changes in the fetal circulation 2; limb weakness associated with decompression sickness 21; and blindness 14.” So, although I am not a doctor, I would recommend that you stay near the surface and use a snorkel 🙂

  6. Michael Sparkman

    I am looking for a chlorine product that wont raise my cya, I use a product now called GLB. Is this a good product?

    • Davy Merino

      HI – GLB is a good brand of chlorine products. Stabilized chlorine tablets are those known as Trichlor, and also Dichlor granular shock. Non-stabilized (without CYA) – that’s any of the hypos – cal hypo, lithium hypo (both granular) or liquid sodium hypo. You could use 5 gallon liquid drums, with the Pool Pal chlorinator, or use Cal Hypo tablets, with a Cal Hypo tablet feeder (do not use a Trichlor feeder or floater). Both systems are a bit pricey however, and the tablets are also expensive (cal Hypo tabs). You could also switch to bromine, which is not stabilized with cya. Or, you could just use Trichlor and use BioActive cya reducer as needed, or replace 1/4 of the pool water every season, to lower cya.

  7. Stablizer question – my salt chlorinator died and I have been using TriChlor tabs. While doing this I have also had to ADD CYA, but everyone is saying that TriChor has stablizer, and using TABS has driven their CYA over the limit?

    I am confused about this – I use ~ 2 3″ tabs a week, 19K gallons. But my CYA reads zero if I do not add any? What is up with that?

    • Hi, Trichlor tablets or sticks do contain a small amount of stabilizer, but it would take months or years for the level from tablets alone to build up to a good cya level, longer for pools that get regular rain, or have small leaks, backwash frequently, or lower the water for winterization, all which dilute the cya concentration. That is why most people will start with adding 20 ppm or so, of cyanuric acid (2 lbs per 10,000 gals), to give an initial boost to untreated water. After that, for many pools, just using tablets will raise the level to 30 ppm or so, by the end of the summer.

  8. Betty ann

    What is the difference in chlorine is it strength and how fast the melt and how much more you use

    • Davy Merino

      There are several types of chlorine, for granular or powdered chlorine there is Calcium hypochlorite and lithium hypochlorite, with calcium being twice as strong as Lithium, but half as easy to dissolve (not as fine). There are Trichlor tablets and Cal Hypo tablets, Trichlor is stabilized and slow dissolve, Cal Hypo is not stabilized and fast dissolving. So, yes you are correct that the main differences between chlorine are dissolution rate and potency, but also other factors like if it is stabilized with cyanuric acid (or not), or if the pH level is high, low or neutral. And know this – all chlorine types are incompatible and will explode or ignite if they contact each other, even just a grain or granule.

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