DICHLOR: BUYER’S GUIDE & FAQ

Dichlor and trichlor are both stabilized chlorine used to sanitize and maintain pools, spas, and hot tubs, however:

• Dichlor is usually granular or liquid, and contains 55 - 62% available chlorine. It dissolves quickly and evenly, making it convenient for regular use. It’s close to pH neutral, meaning it doesn’t impact your pH levels as much as other forms of chlorine.
• Trichlor is usually in tablet form, and contains 90% available chlorine. It dissolves slowly, making it ideal for consistent chlorine delivery via a floating dispenser or automatic feeder. It’s highly effective due to its chlorine content, and has a lower impact on calcium hardness compared to other forms of chlorine.

Yes. Dichlor adds stabilizer (CYA) every time you use it, as it contains approximately 10% cyanuric acid. For every 10 ppm of free chlorine added, it raises CYA by about 9 ppm. Over time, this can lead to reduced chlorine effectiveness, skewed alkalinity readings, and damage to your pool or equipment.

If your CYA levels do get too high, add a Cyanuric Acid Reducer in order to decrease it.

Technically, yes, but it’s usually not recommended for routine use because of how it raises your CYA. Saltwater pools already generate chlorine, so dichlor is typically reserved for the occasional boost.

Your salt water chlorinator is good for maintaining baseline sanitizer levels. However, storms or heavy bather loads, can cause a sudden demand for higher chlorine levels.Using a dichlor shock could be useful for giving it that extra boost to keep your pool clean and clear.

Yes, when pre-dissolved or broadcast properly. It dissolves quickly, but if concentrated granules end up sitting on your liner it can cause bleaching. Dichlor is safe for use with all other types of pool and spa interior surfaces, including plaster and painted finishes.

Dichlor has a near-neutral pH (around 6 - 7), making it less likely to significantly lower pool pH compared to trichlor.

This depends on pool size and current chlorine levels. Typically, 1 pound of dichlor adds about 6 - 7 ppm of chlorine per 10,000 gallons of water. You should always test your water before and after dosing.

Yes! Dichlor is commonly used in spas because it dissolves quickly and is easy to dose in small volumes of water. It is also stable in hot water, making it effective for both daily maintenance and shock treatments.

Dichlor has a long shelf life if kept dry and sealed, however exposure to moisture does reduce potency.

Most dichlor products contain 56% - 62% of available chlorine, depending on the specific product.

It depends on your needs!

• Dichlor is a stabilized form of chlorine, meaning it contains cyanuric acid, which helps to protect your chlorine from degrading due to UV exposure. It usually comes in granular form, and contains 55 - 62% chlorine. It dissolves quickly and evenly, which means it won’t bleach or damage your pool surface, and has less of an impact on pH levels compared to Cal Hypo. However, it adds cyanuric acid to the pool, which can build up over time and lead to chlorine inefficiency, and is also slower acting.
• Cal-Hypo is a widely used pool sanitizer that comes in either tablet or granular form. It’s known for its high chlorine content of 65% - 75% available chlorine, is fast-acting, and very effective at killing bacteria. It doesn’t contain cyanuric acid, allowing you to manage your stabilizer levels separately. It’s ideal for shock treatments due to its rapid dissolution. However, it increases the calcium hardness in your water, which can lead to scaling if overused. It’s also highly reactive, requiring careful handling and storage, and must be pre-dissolved before you add it to your pool to prevent bleaching or otherwise damaging your pool surfaces.

Not usually. It dissolves quickly and is generally clear-dissolving, but improper dosing or high CYA levels can contribute to cloudy water. As it’s sodium-based, it dissolves both quickly and clearly, leaving no turbidity or cloudiness.

High CYA levels from overusing dichlor can reduce chlorine effectiveness, sometimes referred to as “chlorine lock”. If your CYA levels do get too high, add a Cyanuric Acid Reducer in order to decrease it.

Yes. Dichlor is considered stabilized because it contains cyanuric acid. This prevents chlorine burnoff from UV rays, ensuring that your chlorine levels remain stable for longer.