How to Use Leslie's Power Powder Plus 73: Complete Pool Shock Guide

 

TL;DR: Leslie's Power Powder Plus 73 is a calcium hypochlorite (cal-hypo) shock with 73% available chlorine. Add 1 lb per 10,000 gallons for routine shocking, dissolve in bucket first, pour around perimeter at dusk, run pump 8 hours, wait until chlorine drops below 5 ppm before swimming. This guide covers complete dosing, application, safety, and troubleshooting for effective pool shocking.

What is Leslie's Power Powder Plus 73?

Leslie's Power Powder Plus 73 is a premium calcium hypochlorite (cal-hypo) pool shock treatment containing 73% available chlorine. This powerful, fast-dissolving granular shock provides maximum oxidation and sanitization for pools, effectively killing bacteria, destroying algae, and eliminating organic contaminants that cause cloudy water and chloramine buildup.

Key Features of Power Powder Plus 73

• High chlorine content: 73% available chlorine for powerful oxidation
• Calcium hypochlorite formula: Unstabilized shock that won't raise cyanuric acid
• Fast acting: Quickly raises chlorine levels for effective treatment
• Multi purpose: Works for routine shocking, algae treatment, and super chlorination
• No cyanuric acid: Won't contribute to stabilizer buildup
• Safe for all surfaces: Compatible with vinyl, fiberglass, plaster, and tile when used properly
• Long shelf life: Maintains potency when stored correctly
• Professional grade: Trusted by pool service professionals

When combined with proper weekly pool cleaning routines, Power Powder Plus 73 helps maintain pristine water quality and prevents algae growth.

When to Shock Your Pool

Routine Shocking Schedule

Regular shocking is essential for maintaining water quality:

• Weekly shocking: Recommended during peak swim season
• Every 1 to 2 weeks: During moderate use periods
• After heavy rain: Rainwater introduces contaminants and dilutes chemicals
• After pool parties: Heavy bather load requires shocking
• When water appears dull or cloudy: Indicates organic buildup
• Strong chlorine smell: Indicates chloramines, not free chlorine
• Algae appearance: Shock immediately to kill algae
• Spring opening: Shock pool after winter closure
• High cyanuric acid: Cal-hypo shock doesn't add stabilizer

Signs Your Pool Needs Shocking

• Cloudy or hazy water despite proper chlorine levels
• Strong chlorine odor indicating chloramines
• Eye or skin irritation from swimmers
• Algae growth or green tint to water
• Combined chlorine above 0.5 ppm
• After heavy use or contamination
• Water lacks sparkle or appears dull
• High cyanuric acid levels (above 50 ppm)

For comprehensive pool maintenance, follow weekly pool cleaning routines for clear water and avoid common pool cleaning mistakes.

Step by Step Application Guide

Step 1: Test Your Water Chemistry

Before shocking, test your pool water:

• Free Chlorine: Note current level
• Combined Chlorine: Should be below 0.5 ppm
• pH: 7.2 to 7.6 (adjust if needed before shocking)
• Total Alkalinity: 80 to 120 ppm
• Calcium Hardness: 200 to 400 ppm
• Cyanuric Acid: Note level (cal-hypo won't raise it)

Proper pH is critical for shock effectiveness. Learn about balanced pool water for optimal results.

Step 2: Calculate Your Pool Volume

Accurate dosage depends on knowing your water volume:

Rectangular Pools:
Length (ft) × Width (ft) × Average Depth (ft) × 7.5 = Gallons

Round Pools:
Diameter (ft) × Diameter (ft) × Average Depth (ft) × 5.9 = Gallons

Oval Pools:
Length (ft) × Width (ft) × Average Depth (ft) × 6.7 = Gallons

Example: A 20ft × 40ft pool with 5ft depth = 20 × 40 × 5 × 7.5 = 30,000 gallons

Step 3: Determine Power Powder Plus 73 Dosage

Leslie's Power Powder Plus 73 dosage guidelines:

Routine Shocking (Weekly Maintenance)

Standard Dose: 1 lb per 10,000 gallons

• 15,000 gallon pool: 1.5 lbs
• 20,000 gallon pool: 2 lbs
• 25,000 gallon pool: 2.5 lbs
• 30,000 gallon pool: 3 lbs

Heavy Shocking (Algae, Cloudy Water, Heavy Use)

Double Dose: 2 lbs per 10,000 gallons

Super Chlorination (Severe Problems, Green Pool)

Triple Dose: 3 to 4 lbs per 10,000 gallons

High Cyanuric Acid Treatment

When stabilizer is above 50 ppm: Use cal-hypo shock exclusively to avoid adding more cyanuric acid

Step 4: Prepare Power Powder Plus 73 Solution

Proper preparation ensures safe and effective application:

1. Fill a clean plastic bucket with pool water (3 to 5 gallons)
2. Measure the correct amount of Power Powder Plus 73
3. Slowly add shock to water (never add water to shock)
4. Stir gently with a plastic or wooden stick until dissolved
5. Let solution sit for 1 to 2 minutes to ensure complete dissolution
6. Some undissolved particles are normal with cal-hypo

Important: Always add chemicals to water, never water to chemicals. This prevents dangerous reactions and splashing.

Step 5: Add Shock to Pool

Apply shock at dusk or night for maximum effectiveness:

1. Turn on pool pump and ensure it's running
2. Pour dissolved shock solution around pool perimeter
3. Walk around pool, distributing evenly
4. Pour near return jets for better distribution
5. Brush pool surfaces after adding to distribute any settled particles
6. Run pump continuously for 8 to 24 hours
7. Keep pool uncovered during treatment

Step 6: Wait Before Swimming

Allow time for chlorine levels to drop to safe levels:

• Routine shocking (1 lb per 10,000 gal): 8 to 12 hours
• Heavy shocking (2 lbs per 10,000 gal): 12 to 24 hours
• Super chlorination (3 to 4 lbs): 24 to 48 hours
• Always test chlorine before swimming: must be below 5 ppm
• Ideal swimming range: 1 to 3 ppm free chlorine

Step 7: Test and Adjust

After the waiting period:

• Test free chlorine level (should be 1 to 3 ppm)
• Test pH (cal-hypo raises pH, may need adjustment)
• Test combined chlorine (should be below 0.5 ppm)
• Check water clarity
• Adjust chemistry if needed
• Pool is ready for swimming once chlorine is below 5 ppm

Safety Precautions and Handling

Handling Power Powder Plus 73 Safely

• Always wear gloves and safety goggles when handling
• Work in well ventilated area
• Never mix Power Powder Plus 73 with other chemicals
• Add chemicals to water, never water to chemicals
• Keep away from children and pets
• Store in cool, dry place away from other chemicals
• Keep container tightly sealed
• Never use metal containers or utensils
• Wash hands thoroughly after handling
• Don't breathe dust or fumes
• Never mix with chlorine tablets or trichlor products

Storage Guidelines

• Store in original container with lid tightly closed
• Keep in cool, dry location (below 80°F)
• Store away from acids, bases, and other pool chemicals
• Keep away from heat sources and direct sunlight
• Don't store near flammable materials
• Store away from organic materials
• Check container regularly for damage or leaks
• Use within one year of opening for best results

Emergency Procedures

Skin Contact: Rinse immediately with plenty of water for 15 minutes. Remove contaminated clothing. Seek medical attention if irritation persists.

Eye Contact: Rinse immediately with water for 15 minutes, holding eyelids open. Seek immediate medical attention.

Inhalation: Move to fresh air immediately. If breathing is difficult, seek medical attention.

Ingestion: Do not induce vomiting. Drink water or milk. Seek immediate medical attention.

Shocking Schedule and Maintenance

Weekly Pool Shocking Routine

Best Time to Shock: Dusk or night (sunlight degrades chlorine)

Weekly Schedule:

1. Test water chemistry (pH, alkalinity, chlorine)
2. Adjust pH to 7.2 to 7.6 if needed
3. Calculate and measure shock dosage
4. Dissolve shock in bucket of pool water
5. Add to pool with pump running at dusk
6. Run pump overnight (8 to 12 hours)
7. Test chlorine next morning before swimming

Follow comprehensive weekly pool cleaning routines for best results.

Seasonal Considerations

Summer (High Use):

• Shock weekly without fail
• May need to shock twice weekly during peak use
• Shock after pool parties or heavy use
• Monitor chlorine levels more frequently

Spring Opening:

• Shock pool with double dose after opening
• May need multiple shock treatments for green water
• Clean filter thoroughly before and after shocking
• Cal-hypo is ideal for opening if cyanuric acid is high

Fall/Winter:

• Continue weekly shocking if pool remains open
• Reduce frequency to every 2 weeks if usage is minimal
• Shock before closing pool for winter

Pro Tips for Maximum Effectiveness

Expert Tips from Pool Professionals

• Shock at dusk or night: Sunlight degrades chlorine, evening shocking is most effective
• Balance pH first: Shock works best when pH is 7.2 to 7.6
• Pre dissolve shock: Always dissolve in bucket before adding to pool
• Run pump continuously: 8 to 24 hours circulation after shocking
• Brush after shocking: Helps distribute shock and dislodge contaminants
• Clean filter before shocking: Ensures optimal circulation and filtration
• Test before swimming: Always verify chlorine is below 5 ppm
• Use for high cyanuric acid: Cal-hypo won't raise stabilizer levels
• Monitor calcium hardness: Cal-hypo adds calcium to water
• Use quality tools: Employ the best pool brushes for maintenance

Avoid Common Shocking Mistakes

• Shocking during day: Sunlight reduces effectiveness by 50% or more
• Not pre dissolving: Undissolved granules can bleach surfaces
• Adding shock to skimmer: Concentrated chlorine damages equipment
• Not running pump long enough: Minimum 8 hours circulation required
• Swimming too soon: Wait until chlorine drops below 5 ppm
• Ignoring pH: High pH reduces shock effectiveness dramatically
• Mixing with other chemicals: Never mix shock with other products
• Using old shock: Shock loses potency over time
• Not monitoring calcium: Cal-hypo raises calcium hardness

Avoid common pool cleaning mistakes that reduce shock effectiveness.

Maximizing Shock Performance

Water Chemistry: Maintain proper balance for optimal shock performance. High pH dramatically reduces chlorine effectiveness.

Filtration: Run pump 8 to 24 hours after shocking for proper circulation and contaminant removal.

Debris Removal: Skim, brush, and vacuum before shocking to remove organic matter that consumes chlorine.

Timing: Shock at dusk or night when UV degradation is minimal and pool isn't in use.

Calcium Management: Monitor calcium hardness monthly as cal-hypo adds calcium. Learn about managing pool water hardness.

Troubleshooting Common Issues

Problem: Water Still Cloudy After Shocking

Solutions:

• Shock again with double dose
• Lower pH to 7.2 to 7.4 before shocking
• Clean or backwash filter thoroughly
• Run pump continuously for 24 to 48 hours
• Add clarifier to help filter capture particles
• May need algaecide if algae is present

For severe cloudiness, see how to fix green pool quickly.

Problem: Strong Chlorine Smell After Shocking

Solutions:

• This indicates you need MORE shock, not less
• Shock with double or triple dose to break chloramine bond
• Test combined chlorine: should be below 0.5 ppm
• Run pump with cover off to allow off gassing
• Continue shocking until combined chlorine is eliminated

Problem: Algae Returns Quickly After Shocking

Solutions:

• Shock dosage may have been insufficient
• Add algaecide (like No Mor Problems Algaecide or Pool RX Algaecide)
• Brush pool surfaces vigorously daily
• Maintain proper chlorine levels (1 to 3 ppm) between shockings
• Check for high phosphates (algae food source)
• Consider adding solar pool ionizer for continuous algae prevention

For mustard algae specifically, learn about treating resistant algae types.

Problem: Bleached or Damaged Pool Surfaces

Prevention:

• Always pre dissolve shock in bucket before adding
• Never add shock directly to pool
• Brush pool after adding shock to distribute evenly
• Pour shock solution while walking around pool perimeter
• Don't let undissolved granules settle on surfaces

Problem: High Calcium Hardness

Cause: Cal-hypo shock adds calcium with each use

Solutions:

• Test calcium hardness monthly
• If above 400 ppm, partially drain and refill pool (25 to 50%)
• Consider alternating with dichlor shock if calcium is consistently high
• Use calcium reducer products if available

Problem: pH Keeps Rising

Cause: Cal-hypo shock raises pH

Solutions:

• Test pH after shocking and adjust as needed
• Add pH decreaser (muriatic acid or dry acid) to lower pH
• This is normal with cal-hypo shock
• Balance pH before each shocking for consistent results

Frequently Asked Questions

How much Power Powder Plus 73 do I need for my pool?

For routine shocking, use 1 lb per 10,000 gallons. For heavy shocking (algae, cloudy water), use 2 lbs per 10,000 gallons. For super chlorination, use 3 to 4 lbs per 10,000 gallons.

How long after shocking can I swim?

Wait time depends on dosage. Routine shocking: 8 to 12 hours. Heavy shocking: 12 to 24 hours. Super chlorination: 24 to 48 hours. Always test chlorine: must be below 5 ppm before swimming.

What's the difference between Power Powder Plus 73 and dichlor shock?

Power Powder Plus 73 is calcium hypochlorite (cal-hypo) with 73% available chlorine, unstabilized, raises pH and calcium. Dichlor is stabilized, pH neutral, but adds cyanuric acid. Cal-hypo is ideal when cyanuric acid is high.

Should I shock at night or during the day?

Always shock at dusk or night. Sunlight degrades chlorine rapidly, reducing shock effectiveness by 50% or more. Evening shocking allows chlorine to work overnight without UV degradation.

Why does my pool smell like chlorine after shocking?

Strong chlorine smell indicates chloramines (combined chlorine), not free chlorine. This means you need MORE shock to break the chloramine bond, not less. Shock with double dose.

Can I add shock directly to my pool?

No. Always pre dissolve shock in a bucket of pool water first. Adding shock directly can bleach surfaces and damage pool finishes. Never add shock to skimmer.

How often should I shock my pool?

Shock weekly during swim season for routine maintenance. Shock more frequently after heavy use, rain, or if water appears cloudy. With a solar ionizer, you may only need monthly shocking.

Will Power Powder Plus 73 raise my cyanuric acid?

No. Cal-hypo shock is unstabilized and does NOT contain cyanuric acid. This makes it ideal for pools with high stabilizer levels (above 50 ppm).

Will Power Powder Plus 73 raise my calcium hardness?

Yes. Cal-hypo adds calcium to water. Test calcium hardness monthly. If above 400 ppm, partially drain and refill pool. This is normal with cal-hypo shock.

Can I shock and add algaecide at the same time?

No. Shock first, wait 24 hours, then add algaecide. High chlorine levels from shocking will deactivate algaecide if added simultaneously.

Conclusion

Leslie's Power Powder Plus 73 provides powerful, effective oxidation and sanitization with 73% available chlorine. Its calcium hypochlorite formula makes it ideal for routine shocking, algae treatment, and pools with high cyanuric acid levels. By following proper dosing guidelines, safety precautions, and shocking schedules at dusk or night, you can maintain crystal clear, sanitized water all season long.

Key Takeaways

• Routine shocking: 1 lb per 10,000 gallons weekly
• Heavy shocking: 2 lbs per 10,000 gallons for algae or cloudy water
• Always pre dissolve shock in bucket before adding
• Shock at dusk or night for maximum effectiveness
• Balance pH to 7.2 to 7.6 before shocking
• Run pump 8 to 24 hours after shocking
• Wait until chlorine drops below 5 ppm before swimming
• Cal-hypo doesn't raise cyanuric acid (ideal for high stabilizer)
• Cal-hypo raises pH and calcium hardness
• Monitor calcium hardness monthly

For those seeking to reduce shocking frequency and chemical usage while maintaining superior water quality, consider adding a Solar Pool Ionizer which can reduce chlorine needs by up to 85% and decrease the need for frequent shocking while providing continuous mineral sanitization.