How to Raise Pool pH (Without Overshooting It)

A test strip that reads pH 7.0 or lower isn't an emergency, but it's not something to ignore either. Low pH makes your water more acidic than it should be, which means chlorine dissipates faster, swimmers' eyes sting more, and metal fittings or plaster can slowly take damage. The fix is straightforward: add soda ash, in the right amount, and give it time to work before you add more.

Why pH drifts low in the first place

A few things reliably push pH down over time. Rain is mildly acidic and dilutes your buffer. Heavy bather load adds sweat and body oils that skew acidic. Some chlorine products, particularly trichlor tablets and liquid chlorine in certain conditions, nudge pH downward as they're consumed. And low total alkalinity makes pH swing more dramatically in either direction, since alkalinity is what's supposed to hold pH steady. If your pH keeps drifting low every week, it's worth checking alkalinity too, not just treating the symptom.

The target range

Skimmer and most pool professionals use the same standard range. Aim for the ideal band when you can, and treat the acceptable band as "fine, keep an eye on it" rather than "fix this immediately."

If your reading is below 7.2, that's the point where it's worth dosing rather than waiting it out. Above 7.8 is a different problem (too high, not too low) and calls for acid instead of soda ash, so make sure you're reading the right end of the strip before you buy anything.

Soda ash: the standard way to raise pH

Soda ash (sodium carbonate) is the standard product for raising pH in a residential pool. It's sold at any pool supply store, usually labeled simply "pH increaser" or "soda ash." A widely-published rule of thumb, and the one Skimmer's pH calculator uses, is that roughly 6 ounces of soda ash per 10,000 gallons raises pH by about 0.2. That figure scales linearly: a bigger pool needs proportionally more product, and a bigger desired rise needs proportionally more too.

That math is exactly what Skimmer's pH calculator does automatically. Plug in your pool's gallons, your current reading, and your target, and it works out the soda ash dose for you, so you're not doing multiplication poolside with a phone calculator and wet hands.

How to actually add it

• Pre-dissolve the soda ash in a bucket of water first. Adding it dry directly to the pool can cloud the water temporarily and leaves undissolved granules sitting on the bottom or in the skimmer.
• Pour the dissolved solution around the pool's perimeter, ideally with the pump running, so it circulates and mixes rather than settling in one spot.
• Add chemicals gradually rather than all at once, especially if you're making a large adjustment. Splitting a big dose into two smaller doses a few hours apart is safer than one large dose.
• Wait at least a few hours, ideally overnight, before retesting. pH changes don't register instantly, and testing too soon just tells you the water hasn't finished mixing yet.

Why overshooting is the real risk

The most common mistake with soda ash isn't using the wrong product, it's impatience. A reading of 7.0 looks alarming, so it's tempting to dump in a full container "to be safe." But soda ash takes time to fully dissolve and register on a test, and overshooting past 7.6 into the high 7s creates its own problems: cloudy water, scale formation on surfaces and equipment, and chlorine that becomes less effective at sanitizing. Chasing an overcorrection with acid, then chasing that with more soda ash, is how a pool ends up bouncing between extremes for a week instead of settling into range after one dose.

The safer approach is to dose conservatively, wait, retest, and dose again only if you're still below range. This is slower than dumping in a guessed amount, but it's the difference between one calm adjustment and a week of chasing your own tail.

Check total alkalinity if pH won't hold

If you raise pH correctly and it drifts back down within a day or two, total alkalinity is the more likely culprit. Alkalinity acts as a buffer that keeps pH stable, generally targeting 80-120 ppm ideal (60-120 ppm acceptable). Low alkalinity lets pH swing around even after you've corrected it. In that case, raising alkalinity first, typically with baking soda (sized with a total alkalinity calculator), tends to make future pH adjustments hold much better, and is usually the fix pool professionals reach for when a customer says "I keep adding pH up and it doesn't stick."