If you’ve ever asked “Do I really need to shock my pool every week?” – you’re not alone.
It’s one of the most common questions we hear at Poolside Christchurch, especially as the weather warms up and pools start working overtime.
The quick answer?
Often, yes… but not always.
It depends on your pool, the weather, and the type of shock you’re using.
Let’s break it down so you know exactly what your pool needs — without wasting chemicals or risking green water.
Why Shocking Matters
NZ summers are such a combination of weather either too much rain or heating up earlier each year – warmer days, longer sunlight hours, high UV exposure and dry nor’westers.
All of this impacts your pool in two big ways:
- Chlorine burns off faster, even when your levels look fine.
- Algae thrives, especially after warm nights or sudden temperature jumps.
On top of that, we see a lot of:
- garden debris,
- heavy pollen drops,
- sunscreen and body oils,
- and high bather loads on those scorching Canterbury weekends.
Weekly shock helps your chlorine keep up.
When Weekly Shocking Makes Perfect Sense
Here are the times you absolutely should shock weekly:
✔ Your pool gets heavy use
- Kids, friends, BBQ weekends, cannonballs…
- Human use adds oils, sweat, sunscreen, hair products, and bacteria. Regular chlorine kills germs — but it doesn’t oxidise waste efficiently.
- Shock takes care of the stuff regular chlorine can’t.
✔ The weather is consistently warm
Sun + warm water = paradise for algae.
Shocking once a week stops it before it even starts.
✔ You’re noticing cloudy, dull, or “flat” water
Even when the pool looks clean, contaminants build up in the water and your chlorine gets tied up (combined chlorine). Shock breaks all that apart, restoring sparkling clarity.
What If Your Water “Looks Fine”? Use This Instead If..
- your chlorine is holding,
- the pool looks great, and
- it hasn’t had heavy use…
…you don’t always need a full chlorine shock.
Instead, use non-chlorine shock (oxidiser) for a quick refresh.
Why non-chlorine oxidiser is perfect for maintenance:
- Doesn’t spike chlorine
- Doesn’t affect pH
- Doesn’t raise calcium or stabiliser
- You can swim again in 20–30 minutes
- Keeps the water fresh between big shocks
This is especially handy for salt pools, where you want powerful oxidation without adding unnecessary calcium (which can cake your cell).
When You Can Skip a Week
Some pools genuinely don’t need weekly shock – especially early or late in the season. You can skip a week if:
- free chlorine is holding well,
- combined chlorine is nil or very low,
- water is sparkling,
- there’s no chlorine smell,
- no swimming parties,
- and no storms dumping debris into the pool.
Just remember:
If you don’t keep up lightly, you’ll pay heavily later.
Most green pools we treat were under-shocked for 2–4 weeks.
Which Shock Should I Use… and When?
Here’s the simple Poolside Christchurch method:
Weekly Maintenance:
Use non-chlorine oxidiser. Keeps the water clean and fresh.
When You Need Extra Power: Use chlorine shock, especially if:
- water is going cloudy,
- the pool had heavy use,
- there’s any hint of algae,
- or your free chlorine won’t hold.
For Salt Pools:
You can shock – but avoid cal-hypo.
Use non-chlorine shock for regular maintenance and chlorine shock only when absolutely necessary.
The Best Routine for a Problem-Free Summer
Here’s the simplest, most effective system we recommend to our NZ pool owners:
- Weekly non-chlorine shock
- Monthly chlorine shock (or after heavy use)
- Weekly testing (or pop in-store for a pro test)
- Keep your pump running the right hours for the season
- Use Optimiser or Pool Complete for better efficiency
This combo keeps water clear, sanitiser effective and pool care simple.
Final Answer: Do You Need to Shock Weekly?
Most NZ pools benefit from it > yes.
But it doesn’t always need to be chlorine shock.
Think of it like this:
Chlorine does the day-to-day cleaning.
Shock does the deep cleaning.
Your pool needs both.
Want personalised advice? Bring a water sample in-store and we’ll tell you exactly what your pool needs. No more guessing, no more green water.
Happy swimming!
