Pool Shock Comparison

When it comes to pool shock, you have a variety of options. There no single-best option for every pool, but based on your specific pool characteristics, we can figure out the best choice for you.

Knowing your water balance will determine what shock will work best for you. Testing your water before hand will save you time and money and keep a healthy, maintained pool or spa. We recommend the TF100 Test kit as it includes everything needed and is very accurate.

Cal-Hypo Shock
Calcium Hypochlorite
Increases CH (calcium levels)
Higher available chlorine
Best for: Tablet-chlorine pools

Cal-Hypo is a great way to shock your pool, especially if you have high CYA. Cal-Hypo will not add any CYA to your pool, but it will add calcium (increase CH). When it comes to available chlorine, Cal-Hypo is the strongest shock available. The buckets we sell have 73% available chlorine, and the bags have 65% available chlorine.

Pool Supply World Di-Chlor Pool Shock Packs

Di-Chlor Shock
Dichloro-S-Triazinetrione
Granular Form
Quick Dissolving
Lowers pH
Raises CYA levels
Best for: SWG pools and liquid chlorine pools

Di-Chlor Shock is great for shocking your pool if you have high pH levels. It lowers the overall pH levels, however using Di-Chlor Shock will add CYA or Cyanuric Acid (commonly referred to as water conditioner). CYA prevents chemical loss due to evaporation, but too much can reduce the effectiveness of your free chlorine, allowing algae to grow. Below we have included a chart to help determine what levels you will need to be at to prevent this. Keep in mind that if you have high levels of CYA, you will usually have to partially drain your pool to lower CYA levels.

Chlorine CYA Chart

Chlor-Free Shock
Potassium Monopersulfate (sometimes also called MPS)
Chlorine-Free Pool Shock
Quick dissolving
Best for: Indoor pools and spas

Chlor-Free Shock is a great at oxidizing organic pollutants (bodily fluids, sunscreen etc.) in your pool before they combine with chlorine to create chloramines or combined chlorine (also referred to as CC’s). Combined chlorine is the cause for harsh chlorine smells and can be attributed to irritated skin and eyes. The Chlor-Free Shock eliminates organic pollutants at a faster speed than chlorine shock, dropping CC levels faster, and does not need sunlight to be effective. This is especially important for indoor pools or covered spas that get little sunlight. It’s important to note that Chlor-free does prevent the formation of CC, but does not eliminate existing CC, so it’s best used as a preventative method to keep your pool free of combined chlorine. Chlor-free works great with bromine and will lower the pH in your water.

Note: Chlor-free can show up as CC in a CC test. Introducing a reagent to the test will solve this problem. Our recommended test kit, the TF100, has everything you need, including a reagent.

PoolSupplyWorld.com offers a complete selection of Pool Shock: Calcium Hypochlorite, Potassium Monopersulfate, and Dichloro-S-Triazinetrione, all designed to eliminate contaminants within your pool’s water quickly and easily. We offer a variety of shock types in multi-packs, buckets, and bundled kits that you’re sure to love! Keep your pool healthy, fresh, and sparkling with these hard-working sanitizers.