What is the Best Chemical to Shock a Pool With?

When it comes to maintaining a clean and healthy pool, one of the most essential tasks is shocking the water. Shocking your pool helps to eliminate contaminants like bacteria, algae, and organic matter, ensuring that your pool water stays clear and safe for swimming. However, not all pool shock chemicals are created equal. Choosing the right type of pool shock can make a big difference in how effective your pool maintenance routine is. In this blog post, we’ll discuss the best chemicals to shock a pool with and how to choose the right one for your needs.

What Does Shocking a Pool Do?

Shocking a pool is the process of adding a large dose of sanitizer (typically chlorine) to the water to remove contaminants. This action helps break down the buildup of organic matter, including sweat, oils, leaves, and algae, and refreshes the pool’s chlorine levels.

Shocking your pool is important because it:

• Kills bacteria and algae: Over time, regular chlorine levels can’t keep up with the buildup of organic material, leading to a growth of bacteria and algae. Shocking the pool helps to eliminate these problems.
  

• Restores water clarity: Shocking your pool can help clear up cloudy or murky water caused by high levels of organic material.
  

• Reactivates chlorine: After a heavy pool use or after a rainstorm, chlorine levels can drop. Pool shock helps to boost chlorine levels back to a normal level, ensuring the pool remains sanitized.
  

Types of Pool Shock Chemicals

There are several types of chemicals used to shock a pool, and each has its advantages. The best pool shock for your needs depends on several factors, including the type of pool, the pool’s usage, and your preferences. Below are the most common types of pool shock chemicals:

1. Calcium Hypochlorite
   

• Most Popular: Calcium hypochlorite is the most widely used pool shock chemical. It’s a powerful chlorine-based shock treatment that effectively eliminates bacteria, algae, and organic debris.
  

• Effectiveness: It is highly effective in killing bacteria and algae and can handle a heavy load of contaminants.
  

• Advantages:
  

• Fast-acting
  

• Easy to use
  

• Cost-effective
  

• Considerations: Calcium hypochlorite increases the calcium hardness of the pool water, which can lead to scaling if used excessively. Always check calcium levels after use.
  

• Best For: Most pools, especially if there is a heavy load of organic matter or algae.
  

2. Sodium Dichlor
   

• Chlorine-Based Shock: Sodium dichlor is another chlorine-based shock treatment, but unlike calcium hypochlorite, it doesn’t increase calcium hardness. It’s a stabilized chlorine, making it ideal for pools that need frequent shocking.
  

• Effectiveness: Sodium dichlor is a bit gentler on pool surfaces and equipment but still highly effective in killing bacteria and clearing algae.
  

• Advantages:
  

• Doesn’t raise calcium hardness
  

• Doesn’t cause cloudiness
  

• Stabilized chlorine (works better in sunlight)
  

• Considerations: Sodium dichlor is a bit more expensive than calcium hypochlorite.
  

• Best For: Frequent shocking or pools exposed to a lot of sunlight.
  

3. Potassium Peroxymonosulfate (Non-Chlorine Shock)
   

• Oxidizing Shock: Potassium peroxymonosulfate is a non-chlorine shock that breaks down organic matter without raising chlorine levels. This shock treatment works by oxidizing contaminants in the water, such as oils, perspiration, and debris.
  

• Effectiveness: It’s a gentler option that won’t irritate swimmers’ eyes or skin as much as chlorine-based shocks. However, it doesn’t disinfect the water as well as chlorine shock.
  

• Advantages:
  

• No chlorine odor
  

• Does not irritate skin or eyes
  

• Works quickly
  

• Considerations: Potassium peroxymonosulfate does not kill algae or bacteria and is not a substitute for a chlorine-based shock treatment.
  

• Best For: Regular maintenance or when you want to swim right after shocking.
  

4. Lithium Hypochlorite
   

• High-Quality Shock: Lithium hypochlorite is another chlorine-based shock treatment that works quickly to raise the chlorine level and sanitize the pool.
  

• Effectiveness: This shock treatment is effective for quickly eliminating bacteria, algae, and organic matter. It dissolves quickly and doesn’t raise the calcium hardness level.
  

• Advantages:
  

• Doesn’t increase calcium hardness
  

• Dissolves rapidly and works quickly
  

• No cloudiness after use
  

• Considerations: Lithium hypochlorite is typically more expensive than other types of chlorine-based shock.
  

• Best For: Pools that need fast, effective shock without affecting calcium hardness.
  

How to Choose the Best Pool Shock for Your Needs

Choosing the right pool shock depends on several factors. Here’s a guide to help you make the right choice:

1. Pool Type
   

• If you have a vinyl pool, it’s important to avoid using pool shock that could cause staining, so non-chlorine shock or stabilized chlorine may be a better choice.
  

• Concrete or plaster pools can handle any of the chlorine-based shocks, as they’re durable and able to handle the increased chemical load.
  

2. Frequency of Shocking
   

• If you need to shock the pool frequently, sodium dichlor or potassium peroxymonosulfate may be your best choice because they’re less harsh and don’t affect calcium hardness.
  

• For occasional heavy shocking, calcium hypochlorite is ideal as it’s strong and cost-effective.
  

3. Budget
   

• Calcium hypochlorite is the most affordable option for shocking a pool, making it a great choice for pool owners on a budget.
  

• Lithium hypochlorite tends to be more expensive but may be worth it if you’re looking for quick results without raising calcium hardness.
  

4. Water Condition
   

• If your pool has heavy algae growth or contamination, calcium hypochlorite or sodium dichlor is best for eliminating the issue.
  

• If the pool is generally clean but you need to boost chlorine levels or maintain water clarity, non-chlorine shock like potassium peroxymonosulfate is a good choice.
  

How to Shock Your Pool Safely

Once you’ve selected the best pool shock chemical for your needs, here’s how to shock your pool safely:

1. Test the Water: Before adding any shock chemicals, test the pool water to determine the current levels of chlorine, pH, and alkalinity.
   

2. Calculate the Correct Dosage: Follow the manufacturer’s instructions for how much shock to use based on the size of your pool.
   

3. Add Shock to the Pool: Pour the shock into the pool water while the pump and filter are running to ensure even distribution.

4. Wait Before Swimming: Allow the shock to fully dissolve and the chlorine level to drop before swimming. It’s typically recommended to wait at least 8-12 hours.