Should I Turn Off Salt Cell When Shocking Pool? Expert Guide

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Find on Amazon: Taylor K-2006C Pool Test Kit , Liquid Pool Chlorine , Pool Brush

Quick Answer

Yes, you should turn off your salt water generator (salt cell) when shocking your pool. Turn it off before adding any shock chemicals and keep it off until chlorine levels drop back to normal range (1-3 ppm). This typically takes 8-24 hours depending on your shock method and pool conditions.

Why Turn Off Your Salt Cell When Shocking

Salt water generators are designed to produce chlorine at steady, moderate levels. When you shock your pool, you're dramatically increasing chlorine levels - often to 10-30 ppm or higher. Running your salt cell during this time can cause several problems:

• Cell damage: High chlorine concentrations can damage the titanium plates inside your salt cell, reducing its lifespan
• Inefficient shocking: Your salt cell will continue producing chlorine even when levels are already high, making it harder to control exact chlorine levels
• Calcium buildup: High chlorine production combined with shock chemicals can accelerate calcium scale formation on cell plates
• pH fluctuations: Salt cells raise pH during operation, which can interfere with shock effectiveness since chlorine works best at lower pH levels

Complete Shocking Process for Salt Water Pools

Before Shocking

1. Test your water chemistry using a reliable test kit like the Taylor K-2006C
2. Record current free chlorine (FC), pH, total alkalinity (TA), and cyanuric acid (CYA) levels
3. Turn off your salt water generator at the control panel
4. Ensure your pool pump will continue running for circulation
5. Calculate proper shock dosage (10-15 ppm for standard shocking, or use FC/CYA chart if performing SLAM treatment for algae)

During Shocking

1. Add liquid chlorine (sodium hypochlorite) in the evening to avoid UV degradation
2. Pour shock chemicals around the pool perimeter while pump is running
3. For SLAM (Shock Level And Maintain) method used for algae treatment, target FC levels based on your CYA level (typically CYA × 12%). For standard shocking, target 10-15 ppm FC regardless of CYA
4. Brush pool walls and floor thoroughly to distribute chemicals
5. Keep pump running continuously during shock process

After Shocking

1. Test FC levels every 2-4 hours initially, then every 8-12 hours
2. Maintain shock level FC until overnight FC loss is 1 ppm or less
3. Once FC drops to 5 ppm or below, you can restart your salt cell
4. Gradually increase salt cell output to maintain 1-3 ppm FC
5. Resume normal testing and maintenance schedule

Types of Pool Shock and Salt Cell Considerations

Liquid Chlorine (Recommended)

Liquid chlorine (12.5% sodium hypochlorite) is the preferred shock method for salt water pools. It's pure, dissolves completely, and doesn't add unwanted chemicals. Always turn off your salt cell when using liquid chlorine shock.

Cal-Hypo Shock

Calcium hypochlorite shock is effective but adds calcium to your pool. This is particularly concerning for salt water pools since calcium buildup on cell plates is already a common issue. Turn off your salt cell and clean plates more frequently when using cal-hypo.

Dichlor Shock

Sodium dichlor contains cyanuric acid, which builds up over time. While occasional use is acceptable, regular dichlor shocking can lead to CYA levels that are too high (over 60-70 ppm). Always turn off salt cell when using dichlor.

Common Mistakes to Avoid

• Leaving salt cell running: This is the most common error that leads to premature cell failure
• Shocking during daylight: UV rays quickly break down chlorine, making shocking less effective
• Not testing CYA first: Your shock dosage depends heavily on stabilizer levels
• Using pool store shock products: Many contain fillers and additives that can cloud water or damage equipment
• Restarting salt cell too early: Wait until FC drops below 5 ppm to prevent cell damage

Monitoring and Testing During Shock Process

Use a reliable test kit or test strips that read high chlorine levels accurately. The Taylor K-2006C drop-count titration kit can accurately measure high FC levels (up to 20 ppm direct reading, higher with dilution), making it ideal for shock monitoring. Test every few hours initially, as FC levels will drop rapidly at first.

Watch for these signs that shocking is working:

• Water clarity improving
• Chlorine smell dissipating (strong smell indicates chloramines being destroyed)
• Overnight FC loss decreasing to 1 ppm or less
• pH stabilizing (liquid chlorine raises pH initially, while cal-hypo and dichlor lower pH initially)

When to Resume Salt Cell Operation

Restart your salt water generator only when:

• Free chlorine levels drop to 5 ppm or below
• Water is clear and balanced
• pH is between 7.2-7.6
• You've confirmed shock process is complete (minimal overnight FC loss)

Start at a lower output setting initially and gradually increase to maintain your target FC range of 1-3 ppm. Monitor levels daily for the first week after shocking to ensure everything is balanced properly.