Portable Spas NZ MSpa Help Centre Water Care

The New Owner's...

The New Owner's Guide to Sparkling Spa Water (The Bromine Edition)

Updated on Jun 17, 2026

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Welcome to the Club!

Keeping your spa water crystal clear doesn't have to be a chemistry exam. Since you're using 20g Bromine Tablets, you've chosen a method that's gentle on the skin and highly effective in hot water. Here's your simple roadmap to relaxation.

🚀 Phase 1: The Start-Up

Do this when you first fill your spa, or after a water change.

Fill & Circulate: Fill the spa with fresh, clean water. Once the water is above the bubble ring, turn on the circulation pumps and let them run for about an hour to get things moving and help distribute chemicals.

Balance First: Before adding sanitiser, you need a solid foundation. Test your water and adjust the pH to between 7.2 – 7.4. Also check your Alkalinity and Calcium Hardness and adjust if necessary (check your test strip bottle for the ideal ranges).

Why balance first?

Bromine only works in balanced water. If the pH is outside the ideal range, the tablets will still dissolve but they won't convert to active bromide – your test strip will read zero or very low bromine and the water can turn cloudy. Get the pH right first and you'll save yourself a frustrating week of chasing the water.

The Bromine Boost: Now it's time to sanitise.

  • Dosage: Add 1 Bromine Tablet per 400 litres of water.
  • Pro Tip: If your spa holds 1,200 litres, you'd start with 3 tablets. This establishes your sanitiser "bank."

Give it a Double Shock: On a fresh fill the bromine can take up to a week to come up on your test strips. To speed that along, give the spa a double dose of O2 Shock (around 60g per 1,000 litres) at start-up – it helps build the bromide bank faster. If you're using the spa every day, repeat a normal O2 Shock dose every day or two until bromine starts to show on the strips.

📅 Phase 2: Regular Maintenance

The "set and forget" routine.

The Weekly Check

You don't need to obsess, but consistency is key. At least once a week:

  • Test the water: Dip a test strip. You're looking for a Total Bromine level of 3–5 ppm.
  • Feed the floater: Use a floating dispenser or your spa's inline feeder.
  • The rule: One 20g tablet dissolves gradually. Check the dispenser and add/replace tablets to keep that residual steady.
  • Watch the pH: Keep it locked in at 7.2 – 7.4. If the pH drifts out of range, the bromine stops converting and your reading will drop to zero even though there are tablets in the floater.

The Weekly Refresh

Once a week, give your spa a little extra love:

  • Shock it with O2 Shock: We recommend O2 Shock, a non-chlorine shock specially made for spas. Why O2 Shock? You should never mix chlorine-based shock with bromine, and O2 Shock is completely chlorine-free. It oxidises the dead organic matter (oils, sweat, lotions) the filter missed, reactivates your bromide bank, and keeps the water fresh and odour-free.
    • Dosage: 30g per 1,000 litres (about 2 tablespoons for most MSpas).
    • How to use: With the pump running, broadcast O2 Shock directly into the water.
    • Wait time: Just 15 minutes before you can hop back in.
    • Heavy use: Increase to 2–3 times a week for best results.
  • Rinse filters: Pop your filters out and give them a good rinse with a hose to keep the water flowing freely.
Which shock should I use?

For everyday use, an MPS (non-chlorine) shock like O2 Shock is the best choice – it's gentle on your spa and won't clash with bromine. If you ever need a stronger "rescue" for very cloudy water, a Dichlor shock can be used occasionally (it's chlorine-based and adds stabiliser over time, so don't make it a habit). Avoid Cal-Hypo shock – it's too harsh for portable spas and can damage the heater and controls.

💡 Phase 3: Pro Tips for Success

  • Don't overdo it: Adjust the opening on your floating dispenser. If bromine is constantly high (above 5 ppm), close the vents slightly; if low, open them up.
  • Clear water = happy soaker: Maintaining proper chemistry prevents the two biggest spa killers, foam and algae.
  • Cloudy or smelly water? First check your pH is in range (out-of-range pH is the most common reason bromine stops working), then increase your O2 Shock to daily until the water clears.
  • O2 Shock is NOT a sanitiser: It's an oxidiser that cleans and refreshes your water, but you still need your bromine tablets to kill bacteria. Think of it as the perfect partner to your bromine routine.

📝 Quick Reference Cheat Sheet

Step Action Frequency Goal
Start-Up Fill, balance, add tablets, double O2 Shock Once (per refill) Establish a base. 1 tab per 400L.
Test Dip a test strip At least weekly Bromine 3–5 ppm.
Balance Adjust pH At least weekly Keep pH 7.2 – 7.4 (or bromine won't convert).
Shock Add O2 Shock (30g per 1,000L) Weekly (2–3x for heavy use; double on a fresh fill) Clear cloudy water & odours. Wait 15 mins before bathing.
Clean Rinse filters Weekly Ensure good filtration.