How It Works

What is DI water?

DI water (deionised water) is ultra-purified water with the dissolved minerals removed — the same minerals that cause water spots and streaks when they dry on paint, glass and chrome.

Tap water can contain minerals like calcium, magnesium and silica. They’re fine for drinking, but when the water dries, those minerals stay behind as residue. That’s what creates spotting, streaking and that dull “filmy” look — especially on glass.

With DI water, there’s nothing left behind when it dries.

The simple reason DI water dries spot-free

Tap water dries. Minerals don’t.
DI water dries. Nothing is left behind.

How ion-exchange resin actually removes minerals

Inside every Spot Free Rinse tank is mixed-bed ion-exchange resin — two types of resin beads blended together.

As water passes through, the resin does a swap:

  • One resin grabs positive minerals (like calcium and magnesium) and swaps them for hydrogen ions (H⁺)

  • The other resin grabs negative minerals (like chloride, sulfate, bicarbonate) and swaps them for hydroxide ions (OH⁻)

The H⁺ and OH⁻ combine to form H₂O (pure water).

So instead of minerals staying in the water and drying on your surfaces, the resin captures them while the water flows through the system.

How the system works (real-world version)

  1. Wash as normal with your favourite detergent and tap water

  2. Use Spot Free Rinse for the final rinse (between your hose and nozzle)

  3. Rinse everything down like normal

  4. Walk away and let it air-dry — no towel, no blower, no wiping

Because the final rinse has the minerals removed, drying leaves no spots and no streaks.

When do you replace the resin?

The resin doesn’t last forever. Over time it fills up with the minerals it has captured.

You’ll know it’s time when:

  • your TDS meter starts rising on the output, and/or

  • you begin to notice light spotting

Replacing the resin is simple — swap in a refill and you’re back to spot-free.

What you can use it on

Spot Free Rinse is designed for any surface where water spots are a problem:

  • Cars, 4WDs and motorbikes

  • Caravans and boats

  • House windows, glass balustrades and pool fencing

  • Solar panels

Faster finish, less contact, less risk

No towel drying means:

  • less time spent finishing

  • less touching of paint and glass

  • lower chance of micro-scratches and swirl marks