McGrayel Algatec is a specialized algaecide designed to treat green, yellow (mustard), and black algae in swimming pools. Add 1 quart per 10,000 gallons for treatment, brush pool vigorously, run pump 24 hours, clean filter. Works quickly to eliminate all types of algae. This guide covers complete application procedures and best practices for comprehensive algae treatment.
Table of Contents
What is McGrayel Algatec?
McGrayel Algatec is a professional grade, broad spectrum algaecide specifically formulated to eliminate green, yellow (mustard), and black algae from swimming pools. This powerful treatment works quickly to clear all types of algae while providing ongoing protection against recurrence. Algatec is designed to handle the most stubborn algae problems, making it ideal for pools experiencing persistent or multiple types of algae growth.
Key Features of Algatec
- Broad spectrum formula: Treats all algae types
- Fast acting: Eliminates algae quickly
- Powerful treatment: Handles stubborn algae problems
- Multi-algae solution: Works on green, yellow, and black algae
- Easy to use: Simple application process
- Works with shock: Use alongside pool shock for best results
- Safe for all surfaces: Compatible with vinyl, fiberglass, plaster, and tile
- Professional strength: Used by pool service professionals
How Algatec Differs from Single-Purpose Algaecides
Unlike algaecides designed for only one type of algae, Algatec provides comprehensive treatment for all algae types. This eliminates the need to diagnose specific algae strains or purchase multiple products, simplifying treatment while ensuring effective results regardless of which algae type is present.
Why Use Algatec for Pool Care?
Benefits of Multi-Algae Treatment
- Eliminates green algae quickly
- Treats chlorine-resistant yellow (mustard) algae
- Works on stubborn black algae
- Handles mixed algae infestations
- Prevents algae recurrence
- Simplifies algae treatment
- Cost effective comprehensive solution
- Works with all sanitizers
Understanding Different Algae Types
Green Algae: Most common type, appears as green tint or spots, responds quickly to treatment.
Yellow (Mustard) Algae: Chlorine-resistant, appears as yellow or tan spots, typically in shaded areas, brushes off but returns quickly.
Black Algae: Most difficult to eliminate, appears as dark spots, has protective layers and roots that embed in surfaces, requires aggressive treatment.
Algatec is formulated to handle all three types effectively.
When to Use Algatec
Ideal Situations for Algatec
Green Algae Treatment:
- Pool water has green tint
- Green spots on surfaces
- Cloudy green water
- Visible green algae growth
For severe green algae, see how to fix green pool quickly.
Yellow (Mustard) Algae Treatment:
- Yellow or tan colored spots
- Algae that brushes off but returns
- Chlorine-resistant algae
- Algae in shaded areas
Learn about whether solar pool ionizer is effective against mustard algae.
Black Algae Treatment:
- Dark spots on pool surfaces
- Algae that won't brush off easily
- Algae with roots embedded in plaster
- Persistent dark algae spots
Mixed Algae Infestations:
- Multiple algae types present
- Uncertain which algae type you have
- Comprehensive treatment needed
Step by Step Application Guide
Step 1: Test and Balance Water Chemistry
Before treating algae, test and adjust water:
- pH: 7.2 to 7.6 (lower end is better for algae treatment)
- Total Alkalinity: 80 to 120 ppm
- Free Chlorine: Note current level (likely low with algae present)
- Calcium Hardness: 200 to 400 ppm
Learn about how to maintain your pool's pH balance, how to manage pool water hardness, and how solar ionizers support balanced pool water.
Step 2: Calculate Pool Volume
Accurate dosage depends on knowing your pool's water volume:
Rectangular Pools:
Length (ft) Ă Width (ft) Ă Average Depth (ft) Ă 7.5 = Gallons
Round Pools:
Diameter (ft) Ă Diameter (ft) Ă Average Depth (ft) Ă 5.9 = Gallons
Oval Pools:
Length (ft) Ă Width (ft) Ă Average Depth (ft) Ă 6.7 = Gallons
Step 3: Determine Algatec Dosage
McGrayel Algatec dosage guidelines:
Standard Treatment Dosage
1 quart per 10,000 gallons
Dosage Examples:
- 10,000 gallon pool: 1 quart (32 oz)
- 15,000 gallon pool: 1.5 quarts (48 oz)
- 20,000 gallon pool: 2 quarts (64 oz)
- 25,000 gallon pool: 2.5 quarts (80 oz)
- 30,000 gallon pool: 3 quarts (96 oz)
Severe or Black Algae
For very heavy algae or black algae, may need to repeat treatment after 48 hours if algae remains. Black algae may require multiple treatments.
Step 4: Shock Pool First
Critical step for algae treatment:
- Shock pool with calcium hypochlorite or liquid chlorine
- Use 2 to 3 lbs shock per 10,000 gallons for green/yellow algae
- Use 3 to 5 lbs shock per 10,000 gallons for black algae
- Add shock in evening for best results
- Allow shock to circulate for 1 to 2 hours
Step 5: Add Algatec to Pool
Apply algaecide after shocking:
- Shake Algatec bottle well before using
- Measure correct amount based on pool size
- Pour Algatec slowly around pool perimeter
- Walk around entire pool while pouring
- Distribute evenly for best results
- Pour near return jets for better mixing
- Do not add directly to skimmer
Step 6: Brush Pool Vigorously
Essential step for all algae types:
- Use appropriate brush for algae type (stainless steel for black algae)
- Brush entire pool surface thoroughly
- Brush walls from top to bottom
- Brush floor in overlapping strokes
- Brush steps, corners, and crevices
- Focus extra attention on visible algae spots
- Continue brushing for 15 to 20 minutes
- Repeat brushing every 12 hours for black algae
Use the best pool brushes for effective algae removal.
Step 7: Run Pump Continuously
Ensure proper circulation during treatment:
- Run pump continuously for 24 to 48 hours
- Do not turn off pump during treatment
- Allows chemicals to circulate throughout pool
- Filters out dead algae
- Monitor filter pressure closely
Learn about how pool circulation supports proper maintenance.
Step 8: Clean Filter Frequently
Critical for removing dead algae:
- Clean or backwash filter when pressure rises 8 to 10 PSI
- May need to clean filter 3 to 5 times during treatment
- Backwash sand or DE filters thoroughly
- Clean cartridge filters with hose
- Continue until water runs clear
Step 9: Vacuum Pool
Remove dead algae from pool:
- After 24 to 48 hours, vacuum pool thoroughly
- Vacuum to waste if possible
- If vacuuming to filter, clean filter immediately after
- Remove all visible algae debris
- Refill pool to proper level if vacuumed to waste
Post Treatment Maintenance
Immediate Follow Up (First Week)
Daily Tasks:
- Test chlorine levels (maintain 3 to 5 ppm)
- Test pH and adjust to 7.2 to 7.6
- Brush pool surfaces daily (especially for black algae)
- Run pump 24 hours daily
- Monitor water clarity
- Clean filter as pressure rises
After 48 Hours:
- Vacuum pool again if needed
- Test all water chemistry parameters
- Add preventative algaecide
- Continue elevated chlorine (3 to 5 ppm)
- Inspect for remaining algae
Follow a comprehensive pool cleaning checklist for beginners and weekly pool cleaning routines for clear water.
Ongoing Prevention
Weekly Maintenance:
- Test water chemistry 2 to 3 times per week
- Maintain proper chlorine levels (1 to 3 ppm)
- Add weekly preventative algaecide
- Brush pool surfaces weekly
- Vacuum pool weekly
- Clean filter monthly
For ongoing algae prevention, see how to use preventative algaecides and how to use Pool RX algaecide.
Pro Tips for Maximum Effectiveness
Expert Tips from Pool Professionals
- Shock first: Always shock pool before adding Algatec
- Brush vigorously: Brushing is critical for all algae types
- Use correct brush: Stainless steel for black algae, nylon for others
- Run pump continuously: 24 to 48 hours minimum
- Clean filter frequently: Expect to clean 3 to 5 times
- Vacuum to waste: Removes algae from pool completely
- Maintain high chlorine: Keep 3 to 5 ppm during treatment
- Be patient: Complete treatment takes 2 to 5 days
- Prevent recurrence: Use weekly algaecide after treatment
- Practice eco-friendly methods: Learn eco-friendly pool cleaning practices
Avoid Common Mistakes
- Not shocking first: Algatec works best with shock
- Insufficient brushing: Must brush vigorously and frequently
- Turning off pump: Needs continuous circulation
- Not cleaning filter: Clogged filter reduces effectiveness
- Swimming too soon: Wait until chlorine drops below 5 ppm
- Stopping treatment early: Complete full treatment process
- Not maintaining prevention: Algae returns without proper maintenance
- Using wrong brush: Black algae requires stainless steel brush
Maximizing Algatec Effectiveness
Water Chemistry: Maintain pH at lower end (7.2 to 7.4) during treatment for maximum chlorine effectiveness.
Brushing: Brush pool surfaces every 12 hours during treatment to dislodge algae and expose it to chemicals.
Filtration: Run pump continuously and clean filter frequently to remove dead algae.
Prevention: Use weekly algaecide and maintain proper chlorine to prevent algae return.
Troubleshooting Common Issues
Problem: Algae Still Present After 48 Hours
Solutions:
- Shock pool again with double dose
- Add second treatment of Algatec
- Brush pool vigorously (use stainless steel for black algae)
- Clean filter thoroughly
- Run pump continuously for another 24 hours
- Test and balance pH to 7.2 to 7.4
- Verify chlorine is at 3 to 5 ppm
- Black algae may require multiple treatments
Problem: Different Algae Types Present
Solutions:
- Algatec treats all types simultaneously
- Use standard treatment dose
- Brush entire pool thoroughly
- May need extended treatment time
- Focus on most stubborn algae type
- Continue treatment until all algae is gone
Problem: Water Cloudy But Algae Gone
Solutions:
- Continue running pump 24 hours
- Clean filter multiple times
- Add clarifier to help filter capture particles
- Vacuum pool to remove debris
- Test and balance all water chemistry
- May take 3 to 5 days for complete clarity
See how to handle cloudy water in swimming pools and learn about how to use pool clarifiers.
Problem: Algae Returns After Treatment
Solutions:
- Verify chlorine is maintained at 1 to 3 ppm
- Add weekly preventative algaecide
- Test and balance pH to 7.2 to 7.6
- Brush pool weekly
- Clean filter monthly
- Establish consistent maintenance routine
- Consider adding solar ionizer for prevention
Frequently Asked Questions
How much Algatec should I use?
Use 1 quart per 10,000 gallons for standard treatment. For a 20,000 gallon pool, use 2 quarts. For severe or black algae, you may need to repeat treatment after 48 hours.
How long does it take Algatec to work?
Algatec typically shows improvement within 24 to 48 hours when used with shock and proper brushing. Complete clearing may take 2 to 5 days depending on algae type and severity.
Do I need to shock my pool when using Algatec?
Yes! Shocking is essential for Algatec to work effectively. Shock pool first, then add Algatec. The combination kills algae much faster than either product alone.
Can I swim after adding Algatec?
Wait until chlorine levels drop below 5 ppm before swimming, typically 24 to 48 hours after shocking and treating. Test chlorine before swimming.
Will Algatec work on all algae types?
Yes! Algatec is specifically formulated to treat green, yellow (mustard), and black algae. This makes it ideal when you're uncertain which algae type you have or when multiple types are present.
How often should I brush my pool during treatment?
Brush your pool at least twice daily (every 12 hours) during treatment. For black algae, brush vigorously with a stainless steel brush and continue daily brushing for several days.
Can I use Algatec for prevention?
Algatec is a treatment product for existing algae, not a preventative. For prevention, use weekly maintenance algaecides after clearing algae with Algatec.
Can I use Algatec in a saltwater pool?
Yes! Algatec is compatible with all pool types including saltwater, chlorine, bromine, and mineral systems.
Learn about cleaning and maintaining saltwater pools.
Why is my filter pressure so high during treatment?
High filter pressure is normal during algae treatment as the filter captures dead algae. Clean or backwash your filter when pressure rises 8 to 10 PSI above normal.
What's the difference between treating green, yellow, and black algae?
Green algae responds quickest to treatment. Yellow (mustard) algae is chlorine-resistant and may require washing pool accessories. Black algae is most difficult, requiring stainless steel brush, aggressive treatment, and possibly multiple applications.
Can I use Algatec with a solar pool ionizer?
Yes! Algatec treats existing algae while solar pool ionizers prevent future algae growth. Use Algatec for treatment, then add a solar ionizer for ongoing prevention.
Explore what does a pool ionizer do, what is solar pool ionizer, how to choose solar pool ionizer, pool ionizer pros and cons, and the advantages of solar pool ionizers for residential pools.
Conclusion
McGrayel Algatec provides comprehensive treatment for all types of algae in swimming pools, including green, yellow (mustard), and black algae. By following proper application procedures (shock first, add Algatec, brush vigorously with appropriate brush, run pump continuously, clean filter frequently), you can eliminate any algae type within 2 to 5 days. Complete the full treatment process and maintain proper water chemistry to prevent algae from returning.
For long term algae prevention that reduces the need for aggressive treatments like Algatec, consider adding a solar pool ionizer which uses solar power to release copper and silver ions continuously, reducing chlorine needs by up to 85% while providing season long algae and bacteria prevention that helps keep your pool clear and prevents the stubborn algae problems that require Algatec treatment.
