Total Alkalinity Increaser Sodium Bicarbonate

Stabilise hot tub or pool water with pure sodium bicarbonate. Holds pH steady between 7.2 and 7.6 by lifting total alkalinity into the 80-120 ppm comfort band.

• Raises total alkalinity by approximately 10 ppm per 17 g per 1000 L.
• Acts as the pH buffer that stops daily drift.
• Has minimal direct effect on pH at normal dosing.
• Reduces sanitiser consumption by removing pH spikes.
• Improves bather comfort and prevents eye stinging from soft water.

Sizes and prices

• 1kg: £6.32
• 2.5kg: £12.14
• 5kg: £21.84
• 10kg: £41.24
• 20kg: £80.05
• 25kg: £99.45

When you need it

• A fresh strip reads below 80 ppm total alkalinity.
• pH keeps drifting between tests even though you are not dosing.
• Sanitiser drops fast and water looks dull after a refill.
• Bathers report itchy or dry skin after a soak.
• You have just refilled with soft tap water or rainwater.

How to use

1. Test total alkalinity, pH and calcium hardness with a fresh kit.
2. Calculate the dose using the table; never raise TA by more than 30 ppm in one day.
3. Switch the circulation pump on and remove any floating dispenser.
4. Pre-dissolve the dose in 5 L of warm tub water and stir.
5. Pour the solution slowly across the surface with the pump running.
6. Wait 4-6 hours, retest TA and pH, and only redose if TA is still below 80 ppm.

Dosing guide

Doses lift TA roughly 10 ppm. Limit any single dose to 30 ppm; redose the next day if needed. If pH is also low, dose TA first then revisit pH.

• For 1,000 L, add 17 g to reach +10 ppm.
• For 1,500 L, add 51 g to reach +20 ppm.
• For 2,000 L, add 68 g to reach +20 ppm.
• For 5,000 L, add 255 g to reach +30 ppm.
• For 10,000 L, add 510 g to reach +30 ppm.
• For 20,000 L, add 1,020 g to reach +30 ppm.

How it works

Sodium bicarbonate (NaHCO3), commonly called bicarb or baking soda, supplied as a high-purity pool-grade powder with at least 99% active content.

Bicarbonate is the dominant species in pool-grade alkalinity. When pH starts to fall, bicarbonate releases hydroxide ions; when pH rises, it captures hydrogen ions. This buffering action stops day-to-day pH drift.

Without buffer, pH swings 0.4 units a day with normal use, wasting sanitiser and irritating bathers. Holding 80-120 ppm TA cuts sanitiser consumption by up to 40% and protects equipment from acid-base cycling.

Frequently asked questions

What is the ideal total alkalinity?

80-120 ppm for chlorine hot tubs and pools, 80-100 ppm for bromine systems.

How much bicarb raises TA by 10 ppm?

Approximately 17 g per 1000 L of water.

How long until I can bathe?

Wait 4-6 hours with the pump running, then retest pH and TA before bathing.

Is this the same as kitchen baking soda?

Chemically identical. ClearSpa supplies a 99%+ pool-grade bicarbonate, which dissolves cleanly without anti-caking agents.

How long does a 5 kg tub last?

Around 100-200 typical doses for a 1500 L hot tub or 12 months of weekly maintenance for a 30 m3 pool.

Will it work in salt-water systems?

Yes. Salt chlorinators tend to push pH up, so you will use TA increaser less often than with tablets.

Why does TA buffer pH?

Bicarbonate accepts or donates protons depending on pH, so it absorbs the daily acid-base swings before they shift pH.

Does sodium bicarbonate raise pH?

Marginally. Each 100 g per 1000 L lifts pH by about 0.05 units toward 8.3 (its natural buffering point).

Does it raise total dissolved solids?

Yes. 100 g per 1000 L adds about 60 ppm TDS.

Why has TA spiked above 150 ppm?

Either overdosed or top-up water is high in carbonate. Lower with pH minus in 0.4-pH steps until TA drops into band.

Why is my pH rising even after dosing TA?

Bicarbonate slowly drives pH toward 8.3 if dosed heavily. Hold smaller, more frequent doses for smoother buffer.

Why is the water cloudy now?

Powder dosed neat plus high calcium hardness can precipitate calcium carbonate. Filter for 24 hours and add a clarifier.

TA increaser vs pH plus?

TA increaser (sodium bicarbonate) raises buffer with little pH change. pH plus (sodium carbonate) raises pH with little TA change.

TA increaser vs alkalinity-up tablets?

Both contain bicarbonate. Powder is faster to dissolve and easier to dose precisely than slow-release tablets.