Swimming Pool Blog

Chlorine Buyer's Guide

Chlorine Buyer's Guide
by Sean Kerndt March 08, 2013

Swimming Pool Chlorine Buyer's Guide


element of chlorine -
When it comes to keeping a clean and safe pool, nothing is quite as good as Chlorine. Chlorine is the most common chemical used to treat pool and drinking water for bacteria, viruses and other pathogens.
Treating your pool with chlorine not only helps keep your swimming pool water clean but also kills bacteria and prevents algae from forming.
Choosing the best chlorine for your pool depends on factors such as pool type, size and location of the pool.

The best chlorine to buy may be the most convenient source for you, from a dealer with a good price and good service.

3" Tablets or Chlorine Sticks

3 in tablets3 inch chlorine tablets are the most common and popular form of chlorine on the market. Pool owners prefer them because they are the perfect size for floaters and chemical feeders. They are also the ideal size for your average, medium sized swimming pool. Pool stabilizer is added to the mixture during production, to help protect the chlorine molecules from the sun.
Chlorine sticks are identical to 3 inch tablets, and the choice comes down to personal preference. Sticks may be a better option for your particular chlorinator. It is recommended that you use one to two tablets or sticks per 10,000 gallons of water per week.
We also have another type of chlorine called Triple-Action Tabs. These combine a sanitizer, clarifier and algae control in one 3 inch tablet - to make pool care easier.
3 inch chlorine tablets are our top selling chlorine type, which is why they have the cheapest price. When shopping for chlorine tablets, compare the percentage of available chlorine. Our Chlorine tablets are 90% available chlorine, for instance. Also look for the percentage of Trichloro-S-Triazinetrione, which is the chemical name for the stabilized 3 inch chlorine tablets. Our tabs are made of 99% Trichlor... with only 1% of inert binder material.

1" ChlorineTablets

1 inch chlorine tablets are typically used for smaller swimming pools, and in spas. You have greater control over how much chlorine goes into the body of water, which is important because too much chlorine can lead to over-chlorination. Having too much chlorine in a small pool or spa can cause bleaching of bathing suits and skin irritation. The normal dosage of one inch tablets is 25 tablets per week for 10,000 gallons of water.
Smaller tablets also dissolve more rapidly than larger tablets for quicker chlorine levels. 1 inch tablets are generally used in therapy pools, swimspas, hot tubs and are also useful for small portable pools. Fountains without plants or fish use these small tablets to maintain the fountain or water feature. Just like for 3 in. tablets, you can compare 1 in. tablets by their percentage of available chlorine and the % of Trichlor.
Usually, 1 in. tablets are made of the same ingredients as 3 in tablets, they are just a different pressing of the chlorine. We do sell another type of 1 in chlorine tablet, the Cal Hypo tablet, which is also available in a "D" shaped pressing. These types of chlorine require a specific (Cal Hypo) feeder, and should not be used in a feeder meant for (or previously used by) Trichlor tablets.

1" Bromine Tablets

1 in bromine tabsBromine tablets are commonly used to chlorinate hot tubs and spas because it is more stable at high temperatures, and remains potent over a wider range of pH levels. Bromine has many distinct advantages over chlorine such as being less irritating on the eyes and skin, lasting longer, and having a less aggressive odor. While you can use bromine to treat your swimming pool it is much more expensive than using chlorine tablets.

The recommended usage of bromine tablets is 31 tablets per 10,000 gallons of water every five to seven days.
Bromine tablets require a bromine feeder to be dispersed throughout the spa or pool water.

One other distinction between it's cousin Chlorine, is that bromine cannot be stabilized, or protected from the sun. Chlorine tablets are stabilized, that is, a small amount of cyanuric acid is added to each tablet.


Granular Chlorine

granular chlorineGranular chlorine is typically used to raise chlorine levels very quickly by adding large amounts to the swimming pool as a pool shock treatment. Granular chlorine can be used to chlorinate your pool quickly, but for everyday chlorination, tablets provided better results.
Instead of using a chemical feeder like the tablets and sticks, granular chlorine is added directly to the pool water and is normally dispersed before it reaches the bottom of the pool. Slow dissolving forms of granular chlorine must be dissolved in a bucket of water and then added to the pool.
We have several different types of powdered pool shock. Non-Chlorine shock can be used as a replacement for our regular Cal Hypo shock, or our Super Shock. It's easy on vinyl liners, has no smell, and you can swim immediately. Sharing similar benefits is our Lithium Hypo pool shock. Not as powerful at only 35% available chlorine, but clean burning, with no residue - and won't add to calcium hardness levels like Calcium Hypochlorite.
We have buckets of Dichlor shock that is the only stabilized form of pool shock, and the only type not sold in 1 lb bags. Let's see, we also have Assure Multi-Shock which adds the power of Borates to your pool sanitation. Plus, HTH brand pool shock. That's a lot to choose from!
To compare different types of pool shock, compare the percentage of available chlorine, and the price per pound. You'll also need to consider the additional benefits of the shocks that are more costly than Cal Hypo. For more info - see an earlier blog post we did called The Many Types of Pool Shock.

Liquid Chlorine

liquid chlorineLiquid chlorine, aka bleach, is another type of chlorine that you could use in your swimming pool. Swimming pool bleach is a stronger concentration of Clorox bleach, and without any perfumes or ketchup stain fighting additives.

In sunbelt states, it was once popular to chlorinate your inground pool by pouring in some liquid chlorine. Pool guys still today use it on their pool routes. Sodium Hypochlorite, is a fine sanitizer. Inexpensive, clean burning and fast acting. It does however have a few drawbacks.

Liquid can be hard to meter out properly, and it becomes easy to under or over dose the pool. If it's not added daily, you will get peaks and valleys of sanitation - from very high levels of chlorine, to very low levels. Tablets provide a more stable and continuous level of chlorine. Third, the pH level in liquid chlorine is very high, and requires frequent adjustment of your pool pH level.

Liquid chlorine remains the popular choice for large pools however. Commercial pools usually have 50 gallon vats of delivered liquid chlorine. A small metering pump will inject a slow and continuous feed of the light green liquid into the pool return line.

We dont sell liquid chlorine, because it's not possible to ship it. You can usually obtain small amounts at Home Stores, Pool Stores or Water Treatment suppliers.


Salt Chlorine

Surprising last minute entry into our Chlorine Buyer's Guide - but after all, it is a form of chlorine. If you install a salt generator, also called a salt chlorinator, you can make your own chlorine, and never need to buy chlorine again!

Salt Systems work to convert salt in the water into liquid chlorine. All you have to do is add salt to the pool, about 250 lbs per 10,000 gallons. Then, hook up the salt system by plumbing it into the return line, and plugging in the power cord. Electrolysis begins immediately and you can make all the chlorine you need - for free. You can even shock the pool with a salt chlorinator.