Essential Chemicals – Available from Spa Supplies

Test Strips – Made of litmus paper, these strips will test your water’s acidity level in a matter of seconds, and let you know which chemicals your water requires. A good general rule to remember is; when your pH level is in the right zone, your total alkalinity will naturally follow suit. Most test strip bottles will provide a key on the back of the bottle, demonstrating where your chemical levels should be, which will help you ascertain exactly what the water needs. To get a comprehensive chemical reading on your spa pool water, we recommend these test strips.

SPA CHLOR – You probably aren’t surprised to see chlorine near the top of this list. It remains to be the most popular spa pool sanitiser, due to its low cost and effectiveness. Chlorine works by oxidising contaminants, employing molecules to destroy them from the inside. Chlorine will also help to eliminate viruses, bacteria, and effectively prevent the growth of algae.

We must remind you that spa pools fitted with Ultra-Violet Purification and/or Ozone Sanitisation systems can cause false readings for chlorine on test strips. This is because when a correct dosage of chlorine is added, it will clean the water and then be largely burnt off by these systems, leaving your water clean, and chlorine-free. For this reason, we say it’s safe to ignore the chlorine readings on your test strips, as long as you are maintaining the recommended doses after each use of the spa.

pH DECREASE – Will lower your water’s pH level while also lowering its total alkalinity. This will assist you in maintaining your desired pH level of 7.2-7.8 and reduces both eye and skin irritation associated with spa pool water. Lastly, it will help to prevent stains and scaly water.

pH BUFFER – Is used to increase your water’s total alkalinity. TA refers to the total amount of alkaline chemicals (carbonates, bicarbonates & hydroxides) currently dissolved in your spa pool water. You are aiming to have your total alkalinity between 80 and 120ppm (parts per million) – failure to maintain this can cause corrosion of spa parts, as well as difficulty balancing your water.

CALCIUM HARDENER – Total hardness or calcium hardness relates to how much calcium and magnesium are dissolved in your spa pool water. These chemicals are found in most sources of water, but too much or too little in your spa pool can be problematic.

Testing your Water

The easiest part of the process is actually testing your water. Dip one of your test strips into the middle of the spa pool, away from any jets or air blowers, and pull it out immediately. Flick any residual water off the strip and wait about 30 seconds for it to produce your results. Compare your completed test strip to the key on the back of the bottle to ascertain your spa pool’s current chemical levels. This will tell you exactly how or acidic or basic your water is as well as determining whether the water is ‘soft’ or ‘hard’. This information is all you need to decide which chemicals your water needs, and the quantities required.

Balancing your Water

We start with total alkalinity – this relates to the water’s ability to neutralise acids. It acts as a bodyguard for pH, which is why we aim for a total alkalinity reading of 125 – 150ppm (parts per million).

Next up we want to address your water’s pH level. The lower your reading is, the more acidic your water. High readings mean very basic water, we’re aiming for a sweet spot in the middle of the scale, somewhere in the range of 7.2 and 7.8.

Total alkalinity naturally buffers pH which is why they work hand-in-hand. Having your total alkalinity in check will usually push your pH back in line as well. If you need to increase alkalinity, you would use pH Buffer. Likewise, if your alkalinity is too high, you would reach for the pH Decrease. If this process fails to put your pH in the right zone, you would use small amounts of these same chemicals to help it along the way. Having your total alkalinity and pH balanced is essential, as your sanitiser can not do its job without this balance.

After that, we need to look at Calcium Hardness, which is a measure of how ‘hard’ the water in your spa pool currently is. Most running water in New Zealand will be on the soft side unless coming from a well.

Ideally, you want your spa pool water to be slightly on the hard side, as water that is too soft will eat away at your spa’s componentry over time. The ideal level you’re looking for is between 175 and 250ppm. To increase your water’s hardness, you can use Calcium Hardener. If your reading shows that your water is too hard, you can drain approximately ¼ of your spa pool water and refill it. In this circumstance, you would benefit from using a hose filter, which will remove some of the chemicals and minerals present in the water, ensuring you’re refilling your spa with ‘soft’ water.

Shocking your Water

We recommend users ‘Shock’ their spa pool water once a fortnight and/or after heavy usage. This will rid the spa of any organic contaminants such as shampoo, make-up, and dead skin cells. It will also kill any bacteria your normal dose of sanitiser has missed, as well as clear the pool of chloramines that produce an unpleasant smell. This process should clean up any cloudy or green water, and quickly have your water ready for bathing.

We always suggest you dissolve your chlorine in a bucket of water before adding it to your spa water when completing a shock dose. Always remember to run the pumps after your chlorine is added! We also recommend waiting approximately 24 hours before bathing in your spa after a shock, as chlorine levels will be very high straight afterward.

Following these steps will have your spa water looking clear and inviting, while also ensuring you are maintaining your spa’s warranty and not damaging its components. For a more detailed guide, complete with dosage instructions check out our Water Care Handbook.

We understand keeping on top of your water care can be tedious, which is why we have streamlined the process for you. Subscribe to all the products you need through Spa Supplies. You can choose how often you would like to receive the products, with the option to cancel anytime. Subscription members also save up to 30% on the original prices.