How often should I shock my pool to get rid of algae?

Author: Lola Hodkiewicz  |  Last update: Thursday, December 18, 2025

Steps for Preventing Algae If your pool is used frequently, shock it at least once a week.

How long does it take for pool shock to kill algae?

Shocking your pool with chlorine can be an effective method to kill algae. The process can take up to three days and we recommend checking with a pool professional for the amount of shock you should use for your particular pool.

Should I put algaecide or shock first?

The correct process is shock the pool wait 24 hours or for your chlorine levels to drop below 5 PPM then add the algaecide.

Can you shock a pool too often?

Is it possible to shock your pool too much? Yes—excessive shocking of your pool will keep it at an elevated chlorine level. This will cause irritation of the skin and eyes as well as excessive wear and tear on your pool filter system, including excessive corrosion of all metal parts.

Why is my pool shock not killing algae?

It could be you didn't add enough chlorine. It could be that didn't brush the pool well enough first. It could be that your filter isn't performing as well as it could or just needs more time.

How To Clear A Green Pool FAST

What kills pool algae the fastest?

Shocking is the process of adding chemicals to your pool to raise chlorine levels and kill bacteria and algae. We recommend using a calcium hypochlorite shock to treat your algae problems.

Should I vacuum algae before shocking pool?

Not killing algae before trying to remove it.

It is recommended to use a three-part algae treatment. 1) Brush and then perform a heavy shock on your pool. 2) Add an appropriate algaecide to the water while letting the pool equipment run continuously. And 3) vacuum your pool within 36-48 hours.

Is it better to shock a pool day or night?

Unless you're using non-chlorine shock, you should always shock your pool in the evening. Why? Because UV radiation and heat break down chlorine, depleting your chlorine levels by up to 90 per cent in as little as 2 hours.

How often can I shock my pool if it's green?

If you're dipping your toes in the water every couple of days or swimming laps one day a week, you can get away with shocking your pool every other week. Frequent Use: Weekly: If your family is always in the water, however, and is swimming every day, we recommend shocking the pool once a week.

How long does shock last in a pool?

SKIMMER NOTES: As a general rule, most pool chemicals, including pool shock and balancers, should be used within two pool seasons. BUT if you use chlorine and bromine oxidizers and sanitizers, it's best to use them within one season.

How many bags of shock for a green pool?

Use a quadruple dose of shock. One pound of shock treats 10,000 gallons of water. So if you have a 20,000-gallon pool, and your water is dark green, you'll need 6 bags of shock. That's a triple dose.

Can algae grow in a pool with high chlorine?

Algae are microscopic plants that can multiply rapidly when conditions are favorable, even in the presence of high chlorine levels. While chlorine effectively kills algae, high levels can sometimes become ineffective due to factors like poor circulation, pH imbalance, and organic debris.

What is the best pool shock for algae?

Calcium Hypochlorite Pool Shock: Power Powder Plus 73

Leslie's Power Powder Plus 73 is the fastest dissolving granular shock on the market. This particular cal-hypo pool shock is 73% calcium hypochlorite, which means it can handle the toughest algae and bacteria problems.

Should I brush the pool after shocking?

Brush after Adding Chemicals: Many powdered or granular pool chemicals don't dissolve right away when added to the pool water. Brushing helps dissolve and disperse the chemicals so that they aren't able to stain, scale, or etch the interior surface.

How to clear up a green pool fast?

How to Clear Green Pool Water Fast?
  1. Shock the Pool: Use a high dose of chlorine shock treatment. ...
  2. Use an Algaecide: Add an algaecide suitable for your pool type. ...
  3. Clarifying the water: Add a clarifier the next day to bind the dead algae particles and make them easier to filter out.

Can I use algaecide and shock together?

This is because when you mix chlorine and algaecide together, it renders both of them useless. Hence, you should first shock the pool and wait for the chlorine levels to fall below 5 PPM. Only then should you introduce algaecide to get the best results.

Can you put too much shock in a pool?

It's tough to add too much shock to your swimming pool. When you're measuring the amount of shock to put in your pool, it's okay to round up. In fact – it's recommended. You'd have to put an excessive amount of shock in your pool to truly cause dangerous swimming conditions.

Why is algae still in my pool after shocking?

You didn't use Flocculants or Clarifiers. If you still can't see the bottom after shocking your pool, you may need to add a clarifier or flocculant the next day to remove the dead algae. Flocculant binds to small particle impurities in the water, causing them to clump together and fall to the bottom of the pool.

Will baking soda clear a green pool?

As pool experts, we hear this question a lot. The short answer is no; baking soda will not clear a green pool, as it cannot kill algae. Adding baking soda to your pool will, however, raise your alkalinity and pH levels and can be helpful when dealing with small growths of black algae.

How do I get algae out of my pool?

Use a pool brush to vigorously scrub any pool surfaces covered in algae, including the walls, floors and steps. Apply a green algaecide according to the directions on the label. Let the water circulate for 24 hours, then brush the pool surfaces again. Vacuum or backwash to remove any remaining dead algae.

Is shock the same as chlorine?

1) What is the difference between chlorine and shock? Do I need to use both? Chlorine is a sanitizer, and (unless you use Baquacil products) is necessary for maintaining a clear and healthy pool. Shock is chlorine, in a high dose, meant to shock your pool and raise the chlorine level quickly.

How do I know if my pool needs more shock?

Signs your pool needs to be shocked
  1. Low chlorine levels. As part of your ongoing pool maintenance, you should be regularly testing the chemistry and chlorine levels of your pool water. ...
  2. Heavy rainfall. Heavy rainfall can introduce contaminants, such as dirt and debris, into your pool. ...
  3. Cloudy water. ...
  4. Algae growth. ...
  5. Irritation.

How long does it take for shock to clear a pool?

Even if you shock your pool properly, it takes a while for the natural microorganisms to do their job. This can take up to 12-24 hours, as opposed to a couple of days with harsh chemicals. Thus, the pool water takes time to get clear.

Is algae at the bottom of the pool dead?

Once the algae is killed, some of it will be captured in the filter, but because the dead algae particles are so fine, they will settle to the bottom of the pool, usually appearing as a gray or brown dust.

How much pool shock to get rid of algae?

Light green or isolated algae may only require 10 ppm (parts per million) of added chlorine to eradicate. Medium green or yellow blooms may need double the dose. For dark green or black algae, adding enough pool shock to reach 30 ppm may be necessary.

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