Super chlorinating your hot tub is a crucial maintenance step to effectively sanitize the water, eliminate contaminants, and restore clarity. This process, often called shocking, involves adding a concentrated dose of chlorine or a non-chlorine oxidizer to quickly break down combined chlorine (chloramines), destroy bacteria, algae, and organic matter, and neutralize strong odors.
Why Super Chlorinate Your Hot Tub?
Super chlorination is essential for maintaining a healthy and inviting hot tub environment. Here are the primary reasons:
- Eliminate Chloramines: When chlorine reacts with contaminants like sweat, oils, and lotions, it forms chloramines. These are "spent" chlorine compounds that cause strong chemical odors, eye irritation, and reduce chlorine's sanitizing effectiveness. Shocking breaks them apart.
- Kill Bacteria and Algae: A sudden boost of sanitizer eradicates resistant bacteria and prevents or eliminates unsightly algae growth, ensuring your water is safe and clean.
- Restore Water Clarity: Organic waste and fine particles can make your hot tub water cloudy. Super chlorination oxidizes these contaminants, allowing your filter to work more efficiently and restoring sparkling clarity.
- Address Odors: A strong "chlorine" smell in a hot tub is usually due to high levels of chloramines, not free chlorine. Super chlorination removes these odors.
When to Super Chlorinate
Regular shocking is a cornerstone of hot tub care. Consider these intervals:
- Weekly Maintenance: For typical use, a weekly shock treatment helps maintain optimal water quality.
- After Heavy Use: If multiple bathers use the hot tub, or if it's used frequently, shock immediately afterward to combat the increased contaminant load.
- When Water is Cloudy or Smells: These are clear signs that your sanitizer isn't working effectively, and it's time to shock.
- After Refilling: Each time you drain and refill your hot tub, super chlorinate the fresh water to establish a strong sanitizer baseline.
- Before Draining: Some owners shock before draining to help sanitize the plumbing system.
Preparing for Super Chlorination
Before you shock your hot tub, a little preparation goes a long way:
- Test and Balance Water: Use reliable test strips or a liquid test kit to check your water's pH, alkalinity, and calcium hardness. Adjust these parameters if necessary, as balanced water ensures the shock product works most effectively.
- pH: 7.4-7.6
- Alkalinity: 80-120 ppm
- Calcium Hardness: 150-250 ppm
- Clean or Rinse Filters: Dirty filters hinder water circulation and can prevent shock from distributing evenly. Remove and rinse your hot tub filters if they appear dirty.
- Remove Hot Tub Cover: Always remove the hot tub cover during and immediately after shocking to allow gases to escape, preventing chemical damage to the cover.
- Turn Off Air Blowers: If your hot tub has air blowers, turn them off to avoid unnecessary chemical dispersion into the air.
The Super Chlorination Process
Follow these steps carefully to super chlorinate your hot tub effectively:
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Calculate Dosage: Determine the volume of your hot tub to ensure you add the correct amount of shock. A common guideline for super chlorination is 4 teaspoons (tsp) of granular shock per 400 gallons of water. Adjust proportionally for different hot tub sizes.
Hot Tub Volume (Approx.) Super Chlorination Dosage (Granular) 200 gallons 2 tsp 400 gallons 4 tsp 600 gallons 6 tsp 800 gallons 8 tsp -
Prepare the Chemical: Never add granular shock directly to the hot tub without pre-dissolving, as it can bleach or damage the hot tub surface.
- Fill a clean bucket with 1-2 gallons of hot tub water.
- Slowly add the measured shock product to the bucket, stirring gently until completely dissolved. Always add chemicals to water, never water to chemicals.
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Add Shock to the Hot Tub: With the hot tub jets running on high speed (but air blowers off), slowly pour the dissolved shock solution into the hot tub water, ideally near the jets or skimmer to help with rapid dispersion.
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Circulate Water: Allow the water to circulate for at least 20 minutes with the jets running. This ensures the shock is thoroughly mixed throughout the entire hot tub system, including the plumbing.
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Retest and Repeat: After 20 minutes of circulation, retest your water's free chlorine level. If the level is still low, or if the water clarity/odor issues persist, retest and repeat the previous steps (re-calculate, add, and circulate) until the desired effect is achieved. Ideally, you want to see a free chlorine level of 5-10 ppm for an effective shock.
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Aeration (Optional but Recommended): Leave the hot tub cover off for several hours (or overnight) and turn on the jets periodically without the air blowers. This helps to off-gas the chloramines and reduce chlorine levels faster.
Types of Hot Tub Shock Products
While the process is similar, different products can be used for shocking:
- Dichlor (Dichloroisocyanuric Acid): This is a popular granular chlorine shock for hot tubs. It's stabilized, meaning it's less prone to being broken down by UV rays, and dissolves quickly. It adds both chlorine and cyanuric acid (CYA) to the water.
- Non-Chlorine Shock (MPS - Monopersulfate): MPS is an oxidizer that breaks down contaminants without adding chlorine. It's great for regular oxidation between chlorine shocks, as it allows you to use the hot tub sooner. However, it doesn't sanitize as effectively as chlorine.
- Cal-Hypo (Calcium Hypochlorite): While powerful, Cal-Hypo is less commonly recommended for hot tubs due to its tendency to significantly increase calcium hardness levels, which can lead to scale buildup.
After Super Chlorination
- Wait Before Using: Do not use your hot tub until the free chlorine level has dropped back down to a safe bathing range of 1-3 ppm. This can take several hours to a full day, depending on the amount of shock added and the hot tub's usage. Use your test strips to confirm.
- Re-Check Water Balance: Once chlorine levels are safe, re-test all water parameters (pH, alkalinity, calcium hardness) and adjust as needed.
- Monitor Filters: Your filters may accumulate more debris after a shock treatment. Clean or rinse them again if necessary.
Safety Precautions
When handling hot tub chemicals, always prioritize safety:
- Read Labels: Always follow the specific instructions and safety warnings on your chemical product's label.
- Wear Protective Gear: Use gloves and eye protection when handling chemicals.
- Never Mix Chemicals: Never mix different hot tub chemicals together, especially chlorine and non-chlorine shock, as this can create dangerous gases.
- Store Properly: Store chemicals in a cool, dry, well-ventilated area, away from direct sunlight, out of reach of children and pets.
- Ensure Ventilation: Work in a well-ventilated area to avoid inhaling chemical fumes.
By following these guidelines, you can effectively super chlorinate your hot tub, ensuring clean, clear, and safe water for everyone to enjoy.
