Water Scale Inhibitor

Stop calcium scale forming on heaters, jets and waterlines before it starts. A weekly low-dose phosphonate that keeps calcium in solution even where the water is hard.

• Keeps calcium and magnesium in solution so scale cannot form.
• Protects heater elements, jet faces and waterline tiles.
• Slowly frees up flow on lightly scaled equipment over time.
• Works with chlorine, bromine, MPS and salt systems.
• Made for hard-water areas where TH is above 250 ppm.

Sizes and prices

Available in 1L, 2.5L, 5L, 10L, 20L, 25L.

• 1L: £9.78
• 2.5L: £16.35
• 5L: £27.29
• 10L: £49.18
• 20L: £92.95
• 25L: £114.84

How to use

1. Test calcium hardness, pH and total alkalinity.
2. Switch the circulation pump on and take out the dispenser.
3. Pour 10 ml of Water Scale Inhibitor per 1000 L into the skimmer each week.
4. Keep circulation going for at least 30 minutes.
5. Retest pH 24 hours later; rebalance if the drift is more than 0.2 units.
6. Repeat the dose weekly for as long as the water is hard.

Frequently asked questions

How often should I dose?

Once a week as preventative maintenance in hard-water areas.

What counts as hard water?

Water with total hardness above 200 ppm. Most of southern and central England falls in that band.

Will it remove existing scale?

It slowly dissolves light scale over a few weeks. Heavy scale needs descaling at the next water change.

How long does 1 L last?

Around 6 months of weekly dosing for a 1500 L hot tub.

Is it safe for salt-water systems?

Yes. It protects salt chlorinator cells, which scale up especially easily.

Do I still need to balance calcium?

Yes. The inhibitor stops scale forming but it does not replace calcium balancing.

What is the active chemistry?

A blend of organophosphonate (HEDP family) with a low molecular weight polymer for crystal modification.

Does it raise phosphates?

Slightly. 10 ml per 1000 L adds around 1-2 ppm phosphate, well under the algae-feeding threshold for hot tubs.

Will it interfere with sanitiser?

No. At the recommended doses the phosphonate is inert to chlorine, bromine and MPS.

Scale still forming?

Calcium hardness is over 400 ppm or pH over 7.8; refresh water and rebalance.

Cloudy water after dosing?

Existing scale is dissolving; run the filter 24 hours and clean the cartridge.

pH drifting after dosing?

A mild alkali shift; dose pH minus to return to 7.4.

Scale inhibitor or descaler?

Inhibitor prevents new scale and slowly clears light deposits. Descaler is a strong acid product used during a water change to strip heavy scale.

Scale inhibitor or lowering calcium?

Dropping calcium below 150 ppm invites corrosion. The inhibitor lets you keep a safe 200-250 ppm hardness while still blocking scale.