Is your pool water looking a little dull, or have you woken up to a green “swamp”? Adding shock is the most effective way to kill algae and bacteria, but “eyeballing” the dosage is dangerous. Too little chlorine won’t reach the “breakpoint” needed to kill the algae; too much can damage your liner and pump seals.
Use our Pool Shock Calculator to determine the exact amount of liquid chlorine, cal-hypo, or household bleach needed to clear your water. Our tool includes the professional SLAM Method logic for severe algae infestations.
Pool Shock Calculator
How to Use the Pool Shock Calculator
- Pool Volume: Enter your pool’s total capacity in gallons.
- Shock Type: Select the specific product you have. Note that Household Bleach is usually 6%, while Pool Grade Liquid is 12.5%.
- Algae Level:
- Clear: For standard weekly maintenance.
- Cloudy: If the water is hazy but you can still see the bottom.
- Green Swamp: If you have visible algae blooms or the water is dark green.
Why We Built This: The SLAM Secret Sauce
Most online calculators give you a standard “one bag per 10,000 gallons” estimate. This is often insufficient for green pools. Our “Secret Sauce” is the SLAM Method (Shock, Level, and Maintain) integration.
When you select “Green Swamp,” the calculator automatically raises your target bump to 25 ppm. This massive “Chlorine Punch” is necessary to overcome the organic demand of a green pool and fully sanitize the water.
Educational Guide: Choosing Your Shock Type
Not all shock is created equal. Depending on your current chemistry, one type might be better than the others:
1. Cal-Hypo (Calcium Hypochlorite)
The most common dry shock. It is powerful and fast-acting but will increase your pool’s Calcium Hardness levels. Avoid this if you already have scale buildup or hard water.
2. Liquid Chlorine (Sodium Hypochlorite)
Our top choice for gardening and backyard pools. It is purely chlorine and salt; it adds no “extra” chemicals like calcium or stabilizer (CYA) to your water. It is ideal for the SLAM method.
3. Dichlor
A stabilized granular shock. Warning: This adds Cyanuric Acid (Stabilizer) to your pool. If your stabilizer levels get too high, your chlorine becomes “locked” and ineffective, eventually requiring a partial water drain to fix.
Frequently Asked Questions
Q: How long should I wait to swim after shocking?
A: For maintenance shocks (+5ppm), wait at least 8–12 hours. For SLAM shocks (+25ppm), you must wait until the chlorine level drops back below 5 ppm, which may take 24–48 hours.
Q: Can I use regular grocery store bleach to shock a pool?
A: Yes, as long as it is plain, unscented bleach. Our calculator has a specific setting for 6% bleach. Avoid “splash-less” or “scented” versions as they contain soaps that will cause foaming.
Q: Should I shock my pool during the day or at night?
A: Always shock at night. The UV rays from the sun will consume up to 50% of your chlorine in just a few hours. Shocking at night allows the chlorine to work on the algae without interference from the sun.
