Chlorine Basics and Shock Dosing your Spa Pool

If you have taken the plunge and invested in a new spa pool, you’ll want to ensure it’s ready for use on your schedule. One critical component of that is keeping up with your water care and namely your sanitisation. Every time someone enters the spa pool’s water they will be leaving contaminants behind like shampoo, sweat, perfume, etc. Thankfully, we have our friend, chlorine, to help us out by breaking down these contaminants into easy pickings for your filtration system. However, most spa pool owners at one time or another will find themselves with excess contaminants in their spa pool, when this happens the normal doses of chlorine will be insufficient. In this article, we will discuss how to keep on top of your chlorine sanitisation, and how to give your spa pool what we call a ‘shock dose’ when required.

Staying on top of Sanitisation

Adding chlorine straight after you get out of the spa is an excellent way to allow your spa to do some effective cleaning straight after you have left. We know that bacteria thrive in warm, damp environments, so the longer you leave contaminants sitting in your spa water, the more they multiply and work their way deep into your spa pool’s plumbing. Our chlorine is called SPA CHLOR and comes in a granular form. We recommend measuring this by either capful or teaspoon. We also recommend mixing your chlorine in a bucket of fresh water before adding it to your spa pool and running the pumps after adding so it circulates all the way through the spa. An easy rule to remember is adding a small amount of chlorine straight after your soak will go a long way to ensure that bacteria never has a chance to start growing.

Shock Dosing Your Spa Pool

There are many variables at play when it comes to your water’s chemistry. For example, there is going to be a large discrepancy in contaminants entering your pool from two bathers who have just been exercising, as opposed to a couple who have showered before entering. Likewise, sometimes your spa pool water can start to smell, change colour or become cloudy which is generally a sign that your chlorine levels are too low. Fortunately, all of these scenarios can be fixed by giving your spa pool what is known as a ‘shock dose’ of chlorine. This is when you add a larger amount of chlorine than usual to completely rid the water of organic and non-organic contaminants. We recommend you complete this process at least once a fortnight, regardless of how often your spa is being used. The act of shocking your water should quickly clear up the majority of these unwanted scenarios, getting your spa back in pristine condition in a matter of hours. Below is a detailed list of instructions on how to complete a shock dose.

• Measure your required dosage of chlorine.

• Remove your spa’s headrests and cover as they can be affected by oxidation.

• Mix this chlorine into a bucket of fresh water.

• Add the chlorine mix to your spa pool.

• Run the jets to allow our chlorine mix to get deep into the spa’s pipes. Replace the cover after your jets/pumps have completed one time-out cycle – 15 mins.

• Wait 24 hours before bathing due to the high level of chlorine present.

It’s important to wait 24 hours before bathing as the water’s chlorine level will be very high after you perform a shock dose. That 24-hour window will allow the spas ozone to burn a lot of that chlorine off and drop the level to one that is healthy for bathing in. You can cut this window down by increasing the aeration of your water by running the pumps for more than one cycle with the cover off. If you’re not inclined to treat your water with an abundance of chlorine, you can invest in a non-chlorine-based shock, which will perform the same job. This is available in-store in Christchurch and Auckland, with a product called 0² Shock. If you aren’t in Christchurch or Auckland you will be able to find this at your local pool store, you will want to ask for spa-friendly MonoPeroxySulfate. 

Please get in touch with our friendly and helpful customer care team if you have any further questions about using chlorine. For all spa owners, chlorine is an ongoing necessity, so ensure you never run out by subscribing to SPA CHLOR on a term of your choice. Subscribers will save 25% on the total cost, with the option to cancel anytime. 

Please check our full range of Spa Pools | Saunas | Hot Tubs | Swim Spas | Ice Baths | Combo Deals | Accessories or

visit Spa Supplies, New Zealand's favourite shop with everything for your spa pool or sauna! They have Chemicals, Filters, Parts and Accessories - all at incredibly low prices.