Keeping a spa pool clean, clear and comfortable isn’t particularly difficult, but it does require regular attention. Because a spa pool holds a relatively small amount of water and is used at much warmer temperatures than a swimming pool, water quality can change surprisingly quickly.
The good news is that how to maintain a spa pool really comes down to a handful of regular jobs: testing and balancing the water, maintaining the sanitiser level, cleaning the spa, looking after the filter and changing the water when necessary.
For most NZ spa pool owners, a simple maintenance routine is much easier than trying to rescue a neglected spa after the water has turned cloudy, foamy or unpleasant.
What does spa pool maintenance involve?
Spa pool maintenance is the regular care needed to keep the water clean, balanced and safe, while also keeping the pump, filter, heater and other equipment working properly.
The main jobs include:
- Testing the water regularly
- Maintaining the correct sanitiser level
- Checking and adjusting pH
- Keeping total alkalinity at an appropriate level
- Cleaning the spa pool shell
- Cleaning the filter
- Removing debris
- Keeping the cover clean
- Draining and refilling the spa periodically
- Checking the pumps, jets and other equipment
- Taking extra care during periods of heavy use
You don’t necessarily need to spend a lot of time on the spa every day. A few minutes of regular attention can prevent many of the problems that take considerably longer to fix.
How to maintain a spa pool
The easiest way to stay on top of spa pool maintenance is to divide the work into regular tasks rather than waiting until something looks wrong.
Test the water regularly
Water testing should be at the centre of your maintenance routine.
At a minimum, you’ll generally want to monitor:
- Sanitiser level
- pH
- Total alkalinity
- Calcium hardness where relevant
- Cyanuric acid if you’re using a stabilised chlorine product
How often you need to test depends on how frequently the spa is used, the type of sanitiser and the particular system you have.
A spa that’s used by several people several times a week will need more attention than one that’s only used occasionally.
Don’t rely entirely on how the water looks. Clear water doesn’t necessarily mean that the chemistry is correct.
Keep the sanitiser at the right level
Warm water and frequent bathing create a good environment for microorganisms, while sweat, body oils, cosmetics and other contaminants place an additional load on the sanitiser.
Chlorine is commonly used to sanitise spa pools, although some systems use other sanitising methods.
The important thing is to follow the requirements of your particular sanitising system and test the water rather than simply adding chemicals because you think the level is low.
If you’re using chlorine, avoid assuming that adding more is always better. Excessive chlorine can cause unpleasant smells, skin and eye irritation and other water-quality problems.
Your spa manufacturer’s instructions should take priority because recommended levels and procedures can vary between systems.
Keep the pH balanced
pH affects both bather comfort and how effectively chlorine works.
If pH moves too high or too low, you can end up with problems ranging from irritation and scaling to reduced sanitiser performance and potential damage to equipment or surfaces.
Test the pH regularly and make adjustments gradually using the appropriate spa pool chemical.
Don’t make large chemical additions simply because the test result is outside your preferred range. Follow the product instructions and allow the water to circulate as directed before retesting.
Check total alkalinity
Total alkalinity helps the water resist rapid changes in pH.
If alkalinity is too low, pH can become difficult to control. If it’s too high, you may find that pH continually drifts upwards and the water becomes more prone to scaling.
This is one reason I recommend looking at the whole picture when balancing spa pool water rather than continually chasing the pH on its own.
Spa pool water care
Good spa pool water care isn’t just about adding chlorine.
Everything that enters the spa affects the water. This includes sunscreen, moisturiser, deodorant, cosmetics, sweat, dirt and anything else carried into the water by bathers.
That’s why good bather habits can make a noticeable difference.
Before getting into the spa, it’s worth:
- Having a quick shower if practical
- Removing excess cosmetics and lotions
- Avoiding bringing dirt and grass into the spa
- Keeping the cover clean
- Making sure the filter is maintained
The more contaminants that enter the water, the harder your filtration and sanitising system has to work.
Don’t ignore water temperature
Spa pools operate at much higher temperatures than swimming pools, which is one reason water quality can deteriorate quickly.
Higher temperatures can also increase evaporation and chemical demand.
Follow your spa manufacturer’s recommendations for operating temperature, particularly if you’re leaving the spa unused for an extended period.
Cleaning a spa pool
Regular spa pool cleaning is another important part of maintenance.
Even if the water looks clean, contaminants can collect around the waterline, inside the shell, around the jets and in other areas of the spa.
Wipe down the surfaces using products that are suitable for your particular spa. Avoid household cleaning products unless the manufacturer specifically says they’re suitable.
Pay particular attention to:
- The waterline
- Headrests
- Seats and footwells
- Around jets
- The cover
- Areas where debris collects
If you’re cleaning the spa shell after draining it, rinse the surfaces thoroughly before refilling.
You don’t want cleaning product residue ending up in the new water.
Cleaning the spa pool filter
Your filter is responsible for removing suspended particles from the water, so it can become dirty surprisingly quickly.
A dirty filter restricts water flow and makes the filtration system work harder. It can also contribute to cloudy water.
How often you need to clean the filter depends on the spa, filter type and how heavily it’s used.
As a general maintenance routine, inspect the filter regularly and clean it according to the manufacturer’s instructions.
A proper filter clean is particularly worthwhile after:
- Heavy spa use
- Cloudy water
- A water-quality problem
- Draining and cleaning the spa
- A period when the filter has been visibly dirty
Don’t assume that hosing the outside of the cartridge once means the filter is properly clean. Dirt can become trapped between the filter pleats.
How often should you change spa pool water?
There isn’t one universal answer to how often you should change spa pool water.
The ideal interval depends on factors including:
- Spa volume
- Number of bathers
- Frequency of use
- Water chemistry
- Filtration
- Sanitising system
- Water temperature
- How well the spa has been maintained
A heavily used spa may need its water changed considerably more often than one used occasionally.
Rather than treating a particular number of months as an absolute rule, pay attention to the condition of the water and your maintenance routine. If you’re struggling to keep the water balanced or it has developed persistent problems despite correct treatment, draining and starting with fresh water may be the sensible option.
When draining a spa, make sure the discharge method is appropriate for your property and local requirements. Don’t simply pump chemically treated water onto areas where it could cause damage or enter stormwater.
Keeping spa pool water clear
Clear water should be the result of good maintenance rather than something you try to achieve by adding chemicals whenever the water starts looking cloudy.
If your spa becomes cloudy, consider the basics first:
- Test the water.
- Check the sanitiser level.
- Check and adjust pH.
- Inspect the filter.
- Make sure the filtration system is operating correctly.
- Consider how heavily the spa has been used.
- Check whether the water is due for replacement.
Cloudy water can have several causes, so adding more of the same chemical without identifying the problem isn’t always the answer.
Foamy water can also occur when body oils, soaps, detergents and other contaminants accumulate. Persistent foam is a good reason to look at bather habits, filtration and water replacement rather than simply treating the foam itself.
Can spa pools get algae?
They can, particularly when sanitiser levels aren’t properly maintained.
Preventing algae in a spa pool is much easier than trying to deal with an established problem. Keeping the water sanitised, maintaining good circulation and filtration, and cleaning the spa properly all help reduce the risk.
If you have visible algae or the water has developed a strong green colour, don’t simply assume that adding a large amount of chlorine will solve everything. The underlying water chemistry and filtration also need to be addressed.
If the problem is severe or keeps returning, it may be worth getting professional advice.
Draining and refilling a spa pool
Draining gives you an opportunity to properly clean the shell, inspect components and start again with fresh water.
Before draining, check the manufacturer’s instructions. Some spas have specific requirements around draining, plumbing and restarting the equipment.
A typical maintenance process is:
- Turn off the spa equipment as instructed by the manufacturer.
- Drain the water using the spa’s designated drain or an appropriate pumping method.
- Clean the shell and waterline.
- Clean or replace the filter if required.
- Inspect the spa and equipment.
- Refill with suitable water.
- Balance the water.
- Restore normal filtration and heating.
Never run pumps or heaters without the required water level. Running equipment incorrectly while the spa is empty or inadequately filled can cause damage.
Spa pool maintenance through winter
NZ winters can be cold enough that leaving a spa unused for weeks requires some thought.
If you’re continuing to use the spa, your normal maintenance routine still applies. You may simply notice changes in heating time and evaporation.
If you’re not going to use it for an extended period, don’t just leave the water sitting there unattended.
Depending on the spa and its equipment, you may either maintain it in operating condition or properly drain and prepare it for the period of non-use.
This is particularly important in colder areas where freezing conditions can create problems for water-filled plumbing and equipment.
Always follow the manufacturer’s instructions for shutting down a spa for an extended period.
Common spa pool maintenance mistakes
Only testing the water when it looks dirty
Water can have poor chemistry while still looking perfectly clear.
Regular testing gives you an opportunity to correct problems before they become obvious.
Adding chemicals without testing
It’s tempting to add a bit more chlorine or pH adjustment chemical because you think the water needs it.
That can actually make the problem worse.
Test first, then make an appropriate adjustment.
Neglecting the filter
A spa filter is easy to forget because it’s hidden away from view.
However, a dirty filter can affect water clarity, circulation and equipment performance.
Leaving the cover dirty
Your spa cover isn’t just there to keep leaves out. Dirt and contaminants can build up on its underside and around the edges.
Keep it clean and follow the manufacturer’s advice for maintaining it.
Overloading the spa
A small spa with several bathers can receive a surprisingly large amount of contamination in a short period.
If the spa is being used heavily, expect to test and maintain the water more frequently.
Trying to fix every problem with chemicals
Chemicals are only one part of spa maintenance.
If the filter is blocked, circulation is poor or the water is simply overdue for replacement, adding more chemicals isn’t necessarily going to fix the underlying problem.
What to know before maintaining a spa pool
The most important thing to understand is that spa pool maintenance is a combination of water chemistry, filtration, cleaning and good habits.
Don’t concentrate on one area while ignoring the others.
A good routine might look something like this:
| Maintenance task | What to check |
|---|---|
| Regular water testing | Sanitiser, pH and other relevant parameters |
| Water treatment | Adjust chemistry when testing indicates it is needed |
| Filter maintenance | Inspect and clean according to manufacturer instructions |
| Surface cleaning | Waterline, shell, seats and jets |
| Cover maintenance | Clean and inspect regularly |
| Equipment checks | Pumps, jets, heating and circulation |
| Water replacement | Change water when required based on use and condition |
| Seasonal care | Adjust your routine when usage or weather changes |
The exact frequency will depend on your spa and how you use it. A heavily used family spa needs a different maintenance routine from a spa that’s only used occasionally.
When to call a professional
There’s plenty of spa maintenance that a capable homeowner can handle themselves.
Testing water, cleaning the shell, cleaning the filter and carrying out routine maintenance are generally straightforward when you follow the manufacturer’s instructions.
Professional help becomes more appropriate when the problem involves:
- Electrical components
- Faulty pumps or heaters
- Significant plumbing leaks
- Persistent water-quality problems
- Equipment faults you can’t identify
- Damage to the spa shell or structure
- Problems that continue despite correct water maintenance
Don’t work on electrical components yourself unless you’re appropriately qualified to do so. Water and electricity are an obvious combination where taking shortcuts isn’t worth the risk.
If you’re unsure whether a problem is chemical, mechanical or electrical, getting someone experienced to diagnose it can save you from replacing parts unnecessarily.
Frequently asked questions
How often should I test my spa pool water?
The appropriate frequency depends on how often the spa is used and the sanitising system. More frequent use generally means more frequent testing. Follow your spa and chemical manufacturer’s recommendations and test whenever the water appears unusual or after periods of heavy use.
How often should I clean a spa pool filter?
Inspect the filter regularly and clean it according to the manufacturer’s instructions. Heavily used spas may require more frequent cleaning because more contaminants are introduced into the water.
How often should spa pool water be changed?
There isn’t a single interval that suits every spa. Usage, spa size, water chemistry, filtration and sanitising all affect how long water remains suitable. If the water becomes difficult to balance or persistent problems remain despite proper maintenance, changing the water may be appropriate.
Why does my spa pool water go cloudy?
Cloudy water can result from poor water balance, insufficient sanitiser, a dirty filter, inadequate filtration, heavy use or other water-quality problems. Start by testing the water and checking the filter and circulation system rather than immediately adding more chemicals.
Can I use swimming pool chemicals in a spa pool?
Not necessarily. Some chemicals may be suitable for both, while others are designed specifically for spa pools or particular equipment. Always check the product label and your spa manufacturer’s instructions before using a chemical.
How do I keep my spa pool water clean?
Regular testing, correct sanitiser levels, balanced water, good filtration, filter cleaning, surface cleaning and sensible bather habits all work together. Keeping the cover clean and changing the water when necessary also helps.
The key to good spa pool maintenance
You don’t need to spend hours maintaining a spa pool every week, but you do need a consistent routine.
The basic principle behind how to maintain a spa pool is simple: test the water, keep the chemistry balanced, maintain the filter, clean the spa and deal with problems before they become major ones.
If you look after those fundamentals, most spa pool maintenance becomes fairly predictable. The detailed jobs, such as water balancing, filter cleaning, draining and dealing with cloudy water, can then be handled individually when you need more information.
For NZ spa pool owners, the best approach is to build a routine that suits how you actually use the spa rather than relying on a generic maintenance schedule. A spa that’s used several times a week needs more attention than one that sits covered for most of the year, and your maintenance routine should reflect that.
