How to Make Homemade Shock For Your Pool

Originally posted on Men's Journal | By Max Winters | Last updated Jun 30, 2024 7:00 AM ET

One of the most important parts of swimming pool maintenance is preventing bacterial and algae growth by shocking the water with granular pool shock chemicals or liquid chlorine. Pools typically need to be shocked after heavy use or a rainstorm. Commercial pool shock is an easy fix, but as happened a few years ago (during the hottest week of the year just before a big pool party), pool maintenance can become very stressful when the product is in short supply, or when prices skyrocket with seasonal demand.

But there is an easy and affordable fix: homemade pool shock!

This DIY water treatment solution uses common household ingredients to replace the liquid chlorine commercial product that pool owners depend on. Your pool test kit will reveal that even a couple of gallons of bleach is not as strong as a standard pool chlorine (12.5% sodium hypochlorite), so you may need to use more to achieve a clean pool. But for pool owners in a pinch, it's the cheapest pool shock solution you can find.

If you want to go wild on your water chemistry education, we recommend: The Pool Calculator

Try it at Home: You'll Need

These ratios are for a 10,000-gallon pool. Remember to remove any plastic pool toys before beginning treatment.

1 gallon of basic household bleach (unscented, no additives): Kills bacteria and algae. Note that standard disinfectant bleach has an effective shelf life of 6 months and degrades after that.
1 cup of baking soda: raises alkalinity
1/2 cup of borax (sodium tetraborate): raises pH
Large clean bucket
Eye protection
Rubber gloves

Step 1. Measure Dry Ingredients

Put baking soda and borax into the bucket.

Step 2. Mix With Water and Add to the Pool

Gradually add a couple gallons of water and mix well to avoid clumps.
Slowly pour this solution into the pool.
Let the pool filter for at least 30 minutes.

Step 3. Add Bleach to the Pool

Gently pour bleach directly into the pool, distributing it evenly around the edges. A good rule of thumb is to do this in the evening when the sun is not too strong, as UV rays can degrade the bleach solution.

Step 4. Run the Pool Pump

After adding the components of this homemade shock, run your pool pump for 6-8 hours to ensure thorough mixing and circulation.

Step 5. Test Pool Water

Aim for a pH of 7.4 and 7.6. Use a test kit to check for alkalinity levels between 80 and 120 ppm.

The Best Way to Test Your Pool Water

You should test swimming pool water (or hot tubs or plunge pool) about once a week to maintain the correct chemical balance and keep the water clean. There are testing strips and reagents, but they can expire and the results can vary. Sure, you can take the time out of your busy life to take a water sample into your pool supply store and wait for the results, but one of the coolest ways to check your pool water is by using a smart at-home chlorine test kit. These kits come with digital pool readers that analyzes water samples nearly instantly. The results for chlorine levels, pH, alkalinity, and other key parameters are sent to your phone along with a treatment plan. You just make the adjustments and carry on with your day. What could be easier?

This article first appeared on Men's Journal and was syndicated with permission.

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