Sodium bicarbonate that rebuilds your pool's pH buffer — the fix for pH that swings with every dose, and the number to correct before you chase pH at all.
Alkalinity increaser is sodium bicarbonate. Total alkalinity is the buffer that holds pH steady — when it runs low, pH swings with every chlorine dose and rain shower. Test first, raise total alkalinity into the 80–120 mg/L (as calcium carbonate) band set out in our water balance guide, and only then trim pH.
Sodium bicarbonate (NaHCO₃), a mildly alkaline white powder and the standard tool for raising total alkalinity. Its virtue is precision: it lifts alkalinity — the pool's stock of dissolved bicarbonate that soaks up acid and alkali — while moving pH itself only slightly. That is exactly the opposite emphasis to soda ash, which mainly moves pH; the two are companions, not substitutes. Pools running acidic trichlor (TCCA) tablets are the heaviest users, because tablets consume alkalinity dose by dose, week after week. The pool water balance guide explains the buffer in full, including the target band to hold.
| Form | Granular white powder, readily soluble |
| Chemistry | Sodium bicarbonate, NaHCO₃ — total alkalinity buffer |
| Formats | Pack sizes confirmed on enquiry |
| Best for | Pools where pH will not hold steady — especially pools on acidic trichlor tablet chlorine |
| Price | Quoted on enquiry — we reply within one working day |
Test first, then dose — and fix alkalinity before you chase pH. Alkalinity is the foundation: bring it into the band our water balance guide sets out and pH usually settles most of the way by itself, needing only a small trim with pH increaser or pH decreaser afterwards. Done in the reverse order, pH corrections simply refuse to hold. Add bicarbonate in stages with the pump running — broadcast over the surface or pre-dissolved in a bucket of pool water — and retest after a full circulation before the next addition. The dosing calculator gives a starting point for your pool volume.
Expect alkalinity maintenance to be routine rather than a one-off: tablet-chlorinated pools consume the buffer continuously, so a monthly test and periodic top-up is normal. Operators who want the fuller chemistry — how alkalinity, pH and hardness combine into scaling or corrosive water — can read our Langelier Saturation Index explainer, and periodic laboratory testing confirms what strip kits only estimate.
Safety. Sodium bicarbonate is among the mildest pool chemicals, but handle it like the rest: avoid raising dust that can irritate eyes and airways, and 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.
Treat it as routine rather than a one-off. Tablet-chlorinated pools consume the buffer continuously, so a monthly test and a periodic bicarbonate top-up is normal — test and correct before the buffer runs low, and always fix alkalinity before trimming pH. Periodic laboratory testing confirms what strip kits only estimate.
It rebuilds the bicarbonate buffer in the water — total alkalinity — which is what absorbs the daily pushes on pH from chlorine doses, rain, swimmers and top-up water. With the buffer in band the pH moves slowly and corrections hold; with a low buffer the pH swings with every dose no matter how carefully you measure.
Alkalinity first, always. Alkalinity is the foundation the pH reading stands on: correct it into band and the pH often settles most of the way on its own, then needs only a small trim. Chase pH first and you will be dosing corrector week after week while the readings keep drifting.
The usual culprit is acidic chlorine: trichlor (TCCA) tablets consume alkalinity with every dose, and any acid additions to lower pH take it down further. Heavy rain dilutes the buffer too. Pools running tablets year-round normally need a periodic bicarbonate top-up — test monthly and correct before the buffer runs low.
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.