How Often Should I Add Acid To My Pool? And What’s With All This Calcium?

Joshua Abbott
How Often Should I Add Acid To My Pool? And What’s With All This Calcium?
Your Pool Water Isn't Just Off - It's Trying To Tell You Something

If your pool’s starting to look more like a science experiment than a summer paradise, chances are your pH or calcium levels are out of whack. Don't worry — we’ve got your back (and your backyard) at Aquatune.

Table Of Contents:

  1. Thank You Chloe From North Lakes Queensland
  2. So, How Often Do I Need To Add Acid?
  3. Saltwater Chlorinators & pH: The Hidden Climber
  4. Calcium Build-Up – What Gives?
  5. How Do I Fix It?
  6. Got Calcium Or pH Drama? We’ve Got You.

1. Thank You Chloe From North Lakes Queensland

We love hearing from our happy customers — and today, we want to give a huge shout-out to Chloe from North Lakes, Queensland for her kind testimonial!

"I found Aquatune online for my pool chemicals. They are the cheapest around and free delivery is a bonus!"

— Chloe, North Lakes QLD

Thanks so much, Chloe! We're thrilled to hear that you're loving the unbeatable prices and convenience of free delivery from Aquatune. Keeping your pool sparkling clean and well-balanced should be easy — and we’re proud to help make that happen.

Now, to answer your great questions…

"How often to put acid in the pool and how to clear up calcium build up."

2. So, How Often Do I Need To Add Acid?

Pool acid (usually hydrochloric acid) is used to lower your pH so the water stays in the sweet spot — between 7.2 and 7.6. When your pH is too high, chlorine doesn’t work properly, your water goes cloudy and you may end up with a pool that stings eyes faster than a dive-bomb bellyflop.

How often should you add it?

There’s no one-size-fits-all answer. It really depends on:

  • Weather (sunshine and rain both mess with your chemistry)
  • Bather load (the more splashy fun, the more adjustments you’ll need)
  • Other chemicals added (some raise pH as a side effect)
  • Whether you use a saltwater chlorinator (read on...)

3. Saltwater Chlorinators & pH: The Hidden Climber

If you're running a saltwater chlorinator, you might notice your pool’s pH tends to creep up more than a nosy neighbour.

Here’s why:

Salt/Mineral chlorinators convert salt (Sodium/Magnesium chloride) into hypochlorous acid and sodium hydroxide via electrolysis. Hypochlorous acid is your main sanitiser — that’s the good guy. But sodium hydroxide? That’s a strong base and it raises your pH gradually over time.

So while salt/minerals water systems feel softer and gentler (and they are!), they also require regular pH adjustment to stay balanced. That’s where your acid dosing comes in.

Translation? Salt/Mineral pools almost always need a maintenance dose of acid added to stay in the zone. Testing regularly will tell you when.

4. Calcium Build-Up – What Gives?

That white crusty stuff around your pool tiles? That’s calcium scale and no, it’s not a feature of a Roman bathhouse.

Calcium hardness sneaks into your pool every time you top it up. Tap water contains dissolved calcium. As water evaporates, calcium stays behind, building up slowly like an unwanted houseguest.

Things that make calcium worse:

  • High pH (yep, again)
  • High temperatures
  • Poor water balance
  • Leaching from concrete or grout if the water's too "hungry" (lack of calcium in the water) potentially causing tiles to come loose.
  • Too much magnesium hardness may also push calcium hardness out of solution.

5. How Do I Fix It?

To reduce calcium levels:

  1. Drain some pool water – ideally from the bottom, where calcium tends to settle (this is the easiest option).
  2. Use a metal sequestering agent – it binds the calcium and lets your filter system remove it.
  3. Maintain good balance – especially pH and alkalinity, to stop more build-up.

6. Got Calcium Or pH Drama? We’ve Got You.

Check out our Adjusters and Balancers selection of:

👉 Available now at Aquatune.net.au

Keep your pool chemistry smooth, your tiles gleaming and your summer splash-worthy.
Stay balanced.

The Aquatune Team

P.S. Do you have a question about your pool and or spa? Share it with us here and as a small token of our appreciation we will also send you a discount code for $10 off your next order over $75 (which includes free delivery)... https://www.aquatune.net.au/pages/quick-favour 

P.P.S. Do you look after your pool or spa yourself? Join our Do-It-Yourself Pool and Spa Maintenance community here… https://www.aquatune.net.au/pages/diy