How Much Shock Do I Add to My Pool?

The answer depends on two things: your pool size and what you're trying to accomplish. A maintenance shock needs less than a treatment for cloudy water or algae. Here's a straightforward breakdown.

Types of Pool Shock

Before the amounts, you need to know what type of shock you're using — they have different strengths.

Cal-hypo (calcium hypochlorite): The most common. Usually 65-73% available chlorine. Most shock dosing guides are based on this.
Dichlor: About 56% available chlorine. Also adds CYA — avoid if your CYA is already high.
Liquid chlorine (sodium hypochlorite): 10-12.5% concentration. Need more volume but gentler on pool surfaces.
Non-chlorine shock (potassium monopersulfate): Oxidizes without adding chlorine. Good for hot tubs or before swimming quickly.

💡 The amounts below are based on cal-hypo at 65%, which is the most common type sold in 1 lb bags. Adjust proportionally for other types.

Maintenance Shock (Weekly or Bi-Weekly)

For regular maintenance — keeping chloramines in check and the water fresh — use 1 lb per 10,000 gallons.

Pool Size	Amount of Cal-Hypo
10,000 gal	1 lb
15,000 gal	1.5 lbs
20,000 gal	2 lbs
25,000 gal	2.5 lbs
30,000 gal	3 lbs

Problem Shock (Cloudy Water, Heavy Use, After Rain)

Double the maintenance dose — 2 lbs per 10,000 gallons. This raises chlorine high enough to destroy chloramines, kill bacteria, and clear mild cloudiness.

Algae Treatment Shock

Green water or visible algae requires an aggressive treatment. Use 3 lbs per 10,000 gallons as a starting point. For heavy algae, you may need to repeat after 24 hours.

Pool Size	Maintenance	Problem	Algae
10,000 gal	1 lb	2 lbs	3 lbs
15,000 gal	1.5 lbs	3 lbs	4.5 lbs
20,000 gal	2 lbs	4 lbs	6 lbs
25,000 gal	2.5 lbs	5 lbs	7.5 lbs
30,000 gal	3 lbs	6 lbs	9 lbs

How to Add Shock Correctly

Always shock at dusk or after dark — sunlight destroys unstabilized chlorine fast
Pre-dissolve cal-hypo in a bucket of water before adding to the pool (prevents bleaching the liner)
Pour slowly around the perimeter near return jets
Run the pump for at least 8 hours after shocking
Don't swim until chlorine drops below 3 ppm — test before anyone gets in

⚠️ Never add shock directly to the skimmer if you use trichlor tablets in a floater or skimmer. Cal-hypo and trichlor react violently and can cause a fire or explosion.

Wade tells you exactly how much to add.

Enter your pool size once during setup and Wade calculates your exact shock dose every time — for maintenance, cloudy water, or algae treatment.

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How Much Shock Do I Add to My Pool?

Types of Pool Shock

Maintenance Shock (Weekly or Bi-Weekly)

Problem Shock (Cloudy Water, Heavy Use, After Rain)

Algae Treatment Shock

How to Add Shock Correctly

Wade tells you exactly how much to add.

More pool care guides