Chemicals in a spa pool

Spa Chemicals Guide for your Pool

We’re about to flip the lid on everything you need to know about acquiring the right spa chemicals and using them properly. This gyude right here is your handy spa chemicals guideWhether you’re looking to purchase spa chemicals online, setting up your hot tub for the first time, or want to find out about long-term spa care, it’s all here, right at your fingertips.

So sit back and relax (somewhere other than your tub), and soak up the invaluable information this spa chemicals guide has to offer.

In this guide about spa chemicals, we'll cover:

Let’s dive – ahem, carefully step – in.

The spa chemicals you’ll need

Your hot tub pampers you, but this is a reciprocal relationship: it requires a little pampering in return. Your spa’s favourite care ritual? That’d be chemicals. But it’s not just chemicals you need in your spa supplies. Test strips (such as the 3029-H Insta test 4 plus) are an invaluable piece of the spa water chemistry puzzle: without these, you’ll never know what chemicals to add.

It’s best to store your spa chemicals in a locked, hidden cupboard, out of reach for children, pets, and wayward dinner party guests. Remember the chemicals aren’t safe until they’re diluted in your spa. Safety first, people!

Alright, you will need: balancer, sanitiser and cleaning chemicalsLet’s look at each of these in a little more detail.

The three spa chemicals needed

The balancers

To keep your spa balanced, you’ll need these four chemicals on hand:

Your spa needs a certain amount of alkaline substances to prevent acidity from taking over, which can happen quickly with low total alkalinity. Then, if you’ve gone overboard with too much alkalinity, just use some pH reducer to balance it out.

This may seem like a lot of spa pool chemicals already, but you’ll need them all to create the perfect spa water environment.

Sanitiser chemicals

If you’re on the hunt for other spa chemicals, you’re in luck. Because, when it comes to sanitising your spa pool, bromine is your best bet. To elaborate, bromine is a reduced chlorine solution, or in this case, tablet.

Chlorine is an OK option, but it’s possibly not the best chemical to use in your spa. Bromine does the job of sanitising spa water a lot better because it works well in warmer temperatures, whereas chlorine prefers cooler temperatures. You can find out more about the differences between these two products in our bromine guide.

After bromine has protected you from nasty bacteria, you’re left with bromamines which remain in your spa until they’re oxidised. Unlike chloramines, bromamines will keep working at keeping your water safe, and when you add a shock dose to your spa pool, the bromine gets reactivated.

To do this effectively, you’ll need a shock solution: a bromine shock to remove bromamines from your spa or a larger dose of your sanitiser.

These two sanitiser chemicals are critical components of your spa supplies, so be sure to always have them on hand.

Check out our guide about spa sanitisers to learn more information about it.

Spa cleaning chemicals

You won’t need to procrastinate when it comes to spa cleanliness when you have these chemicals to do the job for you:

Water polish will pick up contaminants that your filter can’t manage. In order to avoid build-up of tiny micro-particles that cause cloudy water, you’ll need the help of a coagulant.

Biofilm in spa piping begins to grow very quickly if sanitiser levels are low for a few days. Biofilm is the perfect environment for organisms to live under, and both are stubborn to get rid of. For this reason a pipe cleaner will prevent this unfortunate sequence of events.

Aside from regular cleaning, when the pH levels have been off for some time, foam can appear. Imagine: you’ve got guests coming shortly because news of your new spa pool has leaked, and you’ve lifted the lid to see foam floating around in your spa. Your guests are arriving thick and fast, armed with their togs. You’ll need the help of anti-foam: quick fix for foamy water.

In reality, you’ll only need to use an anti-foam when you don’t have the time to fluff around with balancing the pH levels. It’s just a fast-acting remedy when you’re in a bind.

That’s it for your spa supplies.

Line ‘em up, because in the next section we’ll guide you through when to add these spa pool chemicals to your tub.

Spa chemicals guide: step-by-step

Water first, chemicals second, that’s the golden rule. So first things first, fill up that tub with some good ol’ tap water. Once your spa is filled with water, turn the filter on and leave it to heat up. Then, you’re ready to begin adding your spa pool chemicals.

But hold those horses: always wear your safety gear. This includes a pair of gloves, some safety glasses, and a face mask.

Alright, let’s get into it.

Step one: test the waters

Ok, so you’re not adding chemicals just yet, but you’ll need to test to find out what chemicals make the cut. Use a test strip (such as 3029-H Insta test 4 plus) to find out what levels of pH, alkalinity, and chlorine are in your spa. Here’s how:

  1. Carefully tap out a test strip from the bottle.
  2. Dip the test strip in your spa for a couple of seconds.
  3. Line up the test strip with the colours on the bottle.
  4. Take note of the results.

You’re ready to sanitise your spa pool if the following is in order:

  • Alkalinity is within 100-150 ppm.
  • The pH is between 7.4-7.6.
  • Calcium hardness is within 80-200 ppm.

If your tests are way out of whack, then let’s get that sorted first.

Step two: balance the balancers

Balancing your spa isn’t tricky, but it can be time-consuming.

Each time you add a balancer to your pool, you’ll need to wait 30-60 minutes before you can test again, then repeat this process until the testing strip is in the green.

As with every chemical, the amount you need to add depends on how many litres of water your spa holds. If you’re unsure, check the owner’s manual, wherever you’ve left it, and check the back of each bottle of chemicals for guidelines on chemical concentration.

Then, you’ll need to add your spa pool chemicals in this order:

  1. alkalinity: raise the alkalinity with an alkalinity increaser. This will also raise the pH level.
  2. pH: if the pH is high use a pH decreaser.
  3. calcium hardness: if your water is too soft, raise the calcium level with a calcium hardness increaser

Because bodily residue can cause the pH to rise rather than fall, it’s more common to decrease the pH levels.

Increase the calcium with caution: you can’t decrease the concentration once it’s in your spa, and you’ll need to start all over again by diluting or replacing the water. 

That’s it for balancing! Until next time, of course.

Step three: Sanitise your spa pool

The end is so close you can almost smell it. Yes, it’s now time to add in your sanitiser. To start sanitising your spa pool, you’ll need:

If you’re using bromine all you’ll need to do is add 3-4 bromine tablets into the tablet feeder. Then regularly test the bromine levels: they should be between 3-5ppm.

If you’re using chlorine, simply sprinkle the right amount of spa sanitiser into your water – depending on how often you’re using your spa, you may need to do this daily.

With a successfully balanced and sanitised spa, you can now take some well-deserved time off, soaking in your hot tub. Go on, you’ve earned it!

Spa pool chemicals and maintenance schedule

Maintaining a spa involves a bit of work, so make your spa duties a little easier by setting up a spa maintenance schedule. It will remind you of what spa pool chemicals to add and when. This way, you’ll be less likely to run into problems, such as chemistry imbalances or worse, corrosion of your spa parts.

But chemicals can’t do everything. There are a few tasks that’ll be left up to you, and are just as important as spa pool chemistry. Get your calendar, whiteboard, or whatever will remind you best, and let’s start getting organised.

Thrice-weekly spa maintenance

Everything in our step-by-step spa chemicals guide should be repeated three times a week for optimum water quality. This includes tesnting:

  • water’s alkalinity, pH, and calcium hardness and adjusting as needed.
  • sanitiser levels and adding chlorine granules or tablets to your feeder as needed.

Make sure you always have a good supply of testing strips – you’re going to use a lot of them.

Weekly spa maintenance

Then on one testing day each week, squeeze in the time to:

  • shock your spa.
  • rinse your spa filter.
  • add a dose of water polish and pipe cleaner. 
  • wipe the spa cover and water line with Tile Vinyl Cleaner

If you’re sanitising your spa with bromine, you could use non-chlorinated shockNever mix chlorine granules and bromine tablets together in the same container – not even a little bit – the effects are dangerous.

After the shock treatment, and with freshly cleaned filters, you can then finish up by testing and balancing the spa chemicals. As long as you keep up to date with regular shocking, testing, and adding spa pool chemicals, your spa will remain a safe place to relax.

Quarterly maintenance schedule

Every three months or so will be a monumental day for your hot tub, you’ll need to:

  • drain your spa.
  • flush out the lines.
  • soak the filters in cleaning chemicals, such as filter cleaner and degreaser.
  • scrub down your spa inside and out.

Set aside an entire day, every three months, to empty and refill your hot tub with fresh water. Then while you’re at it, give your spa a good ‘ol scrub down and rinse, and deep clean your filter and lines.

You’ve probably guessed what comes next: that’s right, once you’ve refilled and heated yor tub you’ll need to follow the steps in our spa chemicals guide again.

Refilling your hot tub could come earlier if you’re struggling to balance the pH, or sanitiser levels aren’t rising after adding more bromine. This is an indication that your spa needs a fresh start.

Then, keep rinsing and repeating.

FAQs about spa pool chemicals

If you’re still itching for answers, you’ll probably find them here.

Is there a difference between spa and pool chemicals?

Yes and no. Some spa chemicals are specifically designed to be used in a spa and some pool chemicals are specially designed to be used in a pool.

While some of the balance chemicals are the same, there are also some specialist chemicals that are designed specifically for spas or pools. If you use a pool chemical in your spa, and vice versa, it may cause a radical chemistry imbalance.

If your chemical cupboard is full to the brim and you’re looking for a way to choose one chemical over another, we’ve got one piece of advice: get a bigger cupboard.

Can I use baking soda in my spa?

Alkalinity increaser has the same chemical make up as baking soda. You can also use alkalinity increaser for scrubbing the waterline – just sprinkle a little on a damp cloth and scrub any pesky tile line stains away.

Don’t use household cleaning products as they can cause havoc with your water chemistry!

Should you use bromine or chlorine in a hot tub?

The award goes to: bromine! Bromine is more effective in hot tubs because it works better at temperatures higher than 24°C. On the other hand chlorine can oxidise quickly in warmer temperatures and it remains stable at temperatures below 18°C, meaning you’ll need to be adding chlorine much more often.

If you prefer to spend less time and money on sanitising your spa, and want better results, stick with bromine tablets.

What should I do if the bromine levels are too high?

Bathing in a spa that has too much sanitiser can cause serious skin reactions. So if you’ve tested your bromine levels and the results show anything higher than 5ppm you’ll need to partly drain your spa and top up with fresh water to try and balance it out.

If you do this though, you’ll need to start at step one of our spa chemicals guide.

Shiny spa pool, huh? 

If you need more information, we suggest you reading our spa cleaning guide. 

About the author
Adrian Hill
Adrian Hill

Hey! I'm Adrian, founder and pool expert here at Dolphin Pacific. I love spending time with family, fishing, and have been known to brew my own beer.

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