Pool chemicals · pH調高劑
pH increaser (soda ash)
Sodium carbonate that lifts a low pH back into the 7.2–7.8 band — the fix for corrosive water, stinging eyes and chlorine that disappears too fast.
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Sodium carbonate that lifts a low pH back into the 7.2–7.8 band — the fix for corrosive water, stinging eyes and chlorine that disappears too fast.
pH increaser is soda ash — sodium carbonate. Use it when a test shows pH below 7.2, where the water turns corrosive, stings eyes and eats chlorine. Test first, dose in small steps, retest after circulation. It nudges total alkalinity up a little too; if alkalinity itself is low, fix that first.
Sodium carbonate (Na₂CO₃), the standard alkaline corrector for pool water — typically supplied as a free-flowing white granular powder that dissolves readily. A measured dose neutralises excess acidity and lifts pH back towards the working band, with a modest upward nudge to total alkalinity as a side effect. It is the natural companion to trichlor (TCCA) tablets: tablets are strongly acidic and pull pH down with every dose, so tablet-fed pools are the ones that most often need pH increaser on the shelf. Pools on sodium hypochlorite usually drift the other way and need the pH decreaser instead.
| Form | Granular white powder, readily soluble |
| Chemistry | Sodium carbonate (soda ash), Na₂CO₃ — alkaline pH corrector |
| Formats | Pack sizes confirmed on enquiry |
| Best for | Pools where pH tests below 7.2 — commonly pools running acidic trichlor tablet chlorine |
| Price | Quoted on enquiry — we reply within one working day |
Test first, then dose — never the other way round. If pH reads below 7.2, add soda ash in small increments with the pump running: pre-dissolve it in a bucket of pool water or broadcast it over the deep end, then retest after the water has fully circulated before adding more. Small steps matter because overshooting swaps one problem for another — a pH above 7.8 weakens chlorine and invites scale. The dosing calculator gives you a starting point for your pool volume, and the pool water balance guide explains the bands you are aiming for.
If corrections will not hold — pH sags again within days — check total alkalinity before adding more soda ash. Alkalinity is the buffer that keeps pH steady; when it is low, no amount of pH corrector sticks. Bring it into band with the alkalinity increaser first, then trim pH. Operators who want the fuller picture of how pH, alkalinity and hardness interact can read our Langelier Saturation Index explainer, and periodic laboratory testing confirms what strip kits only estimate.
Safety. Soda ash is alkaline: the dust irritates eyes, skin and airways, so handle with gloves and eye protection and avoid raising dust. Never mix it — or any pool chemical — with chlorine products or acids; add each chemical to the pool separately. Store cool, dry and sealed, away from acids and chlorine, and keep away from children. Safety data sheets are available on request: see the SDS library.
Prices and pack sizes are quoted on enquiry — we reply within one working day. Delivery across Hong Kong; ask about a standing delivery for estates and operators.
Test first. If pH reads below 7.2, add soda ash in small increments with the pump running — pre-dissolved in a bucket of pool water or broadcast over the deep end — then retest after the water has fully circulated before adding more. Small steps matter because overshooting above 7.8 weakens chlorine and invites scale. The dosing calculator on the pool chemicals page gives a starting point for your pool volume, and pack sizes are confirmed on enquiry.
When a test shows pH below 7.2. Acidic water corrodes metal fittings and grout, stings eyes and skin, and burns through chlorine faster than it should. Always test before you dose — never add pH corrector on a hunch — then dose in small steps and retest after the water has circulated.
Usually the chlorine you run. Trichlor (TCCA) tablets are strongly acidic and pull pH and alkalinity down with every dose, and rain and top-up water can add to the drift. If corrections will not hold, check total alkalinity: with a low buffer the pH swings no matter how carefully you dose.
Somewhat. Soda ash mainly raises pH but nudges total alkalinity up as a side effect. If alkalinity itself is low, correct it first with sodium bicarbonate (alkalinity increaser), then trim pH — fixing them in that order means the correction actually holds.
Send us your latest test readings — or the pool size and a photo of what you use now — and we'll tell you what to correct, in what order. No obligation.