How to Bring pH Up in Pool: The Chemistry Behind Crystal Clear Water

I've been maintaining pools for over two decades, and if there's one thing that consistently trips up pool owners, it's pH management. Low pH is particularly sneaky because your pool might look perfectly fine while quietly eating away at your equipment and making swimmers uncomfortable. Let me walk you through what I've learned about raising pH levels effectively – and more importantly, understanding why it matters.

The pH Sweet Spot and Why Your Pool Keeps Missing It

Pool water naturally wants to become acidic. Rain, swimmer waste, chlorine breakdown – they all push pH downward. When I first started in this business, I thought pH was just another number to check off the list. Then I watched a brand-new heater fail after just two seasons because the owner kept their pH at 6.8, thinking "close enough" was good enough.

The ideal range sits between 7.2 and 7.6, with 7.4 being the golden number. This isn't arbitrary – it matches the pH of human tears and mucous membranes. When your pH drops below 7.0, you're essentially swimming in weak acid. Your eyes burn, your skin feels tight, and your expensive pool equipment starts corroding from the inside out.

What really opened my eyes was learning that pH affects everything else in your water chemistry. Low pH makes chlorine hyperactive – it works too fast and burns off quickly. You end up using more chemicals, spending more money, and still having water quality issues. It's like trying to clean your house with undiluted bleach; sure, it's powerful, but it's also destructive and wasteful.

Reading the Signs Before Testing

After years of troubleshooting pools, I've developed a sixth sense for low pH. The water has a particular clarity – almost too clear, with a slight blue-green tint that's different from the healthy blue of balanced water. Metal fixtures develop a telltale etching pattern. Concrete surfaces feel rougher than they should.

But here's what most people miss: the smell. Low pH pools have a sharp, almost metallic chlorine odor that's distinctly different from the clean chlorine smell of a balanced pool. Once you learn to recognize it, you can diagnose pH problems from across the yard.

Testing remains crucial, though. I prefer drop tests over strips for accuracy, especially when dealing with pH issues. Digital meters work well too, but they require regular calibration – something I learned the hard way after giving bad advice based on a meter that hadn't been calibrated in months.

Soda Ash: The Workhorse of pH Adjustment

Sodium carbonate, or soda ash, is my go-to for raising pH. It's predictable, effective, and doesn't significantly impact alkalinity. The key is understanding that soda ash is powerful stuff – a little goes a long way.

For every 10,000 gallons, six ounces of soda ash typically raises pH by 0.2. But here's where experience matters: that's in ideal conditions. Heavy bather load, recent rain, or high chlorine demand can all affect how your pool responds. I always start with 75% of the calculated dose, then retest after four hours.

The biggest mistake I see is dumping soda ash directly into the skimmer. Yes, it dissolves quickly, but it creates a high-pH zone that can precipitate calcium and clog your equipment. Instead, I pre-dissolve it in a bucket of pool water. Takes an extra minute but saves hours of maintenance headaches later.

Distribution matters too. I walk around the pool, pouring the solution in a steady stream with the pump running. Some folks use the "broadcast method," tossing dry soda ash across the surface. It works, but I've seen too many bleached swimsuits from undissolved granules to recommend it.

Baking Soda: The Gentle Alternative

Sodium bicarbonate – regular baking soda – raises pH too, but much more gradually. It's my choice when pH is just slightly low (7.0-7.2) and alkalinity also needs a boost. The relationship between pH and alkalinity is like a dance partnership; you can't adjust one without affecting the other.

I discovered baking soda's gentleness by accident years ago. A customer accidentally bought 50 pounds of baking soda instead of soda ash. Rather than waste it, we used it to slowly bring their chronically low pH up over several weeks. The result? The most stable water chemistry they'd ever had.

The dosage is higher – about 1.5 pounds per 10,000 gallons to raise pH by 0.1 – but the forgiveness factor makes it worthwhile for beginners. You almost can't overdose with baking soda, whereas soda ash overdoses can spike pH above 8.0 and cloud your water with calcium precipitation.

Borax: The Secret Weapon Nobody Talks About

Here's something most pool stores won't tell you: plain 20 Mule Team Borax from the grocery store raises pH without significantly affecting alkalinity. This is golden when your alkalinity is already high but pH keeps dropping.

I stumbled onto borax during a particularly frustrating season where nothing seemed to stabilize a client's pH. Traditional chemicals would spike it up, only to crash again within days. Borax not only raised the pH but seemed to buffer it, reducing the frequency of adjustments needed.

Use about half a pound per 10,000 gallons to raise pH by 0.1. The borates also act as a mild algaecide and make the water feel silkier. Some people maintain 30-50 ppm of borates year-round for these benefits. Just be aware that borates don't evaporate or degrade – the only way to lower them is through dilution.

The Aeration Trick That Changes Everything

Want to raise pH without adding any chemicals? Increase aeration. Running water features, pointing return jets upward, or even vigorous brushing all drive off dissolved CO2, naturally raising pH.

This clicked for me when I noticed that pools with waterfalls always had more stable pH. The constant aeration acts as a natural pH buffer. Now, when I'm dealing with chronically low pH, I first look at water circulation patterns. Sometimes the fix is as simple as adjusting a return jet to create more surface agitation.

For stubborn cases, I'll run an air compressor with a diffuser stone overnight. It's like giving your pool a deep breath – pH rises naturally without affecting other chemistry parameters. This method is particularly useful when you're already at the upper limit of recommended alkalinity but still fighting low pH.

Timing and Temperature: The Overlooked Variables

Water temperature dramatically affects chemical efficiency. Soda ash dissolves and reacts faster in warm water, but it also means you might overshoot your target. In cold water (below 60°F), I increase doses by about 20% and allow extra circulation time.

The best time to adjust pH? Evening, after the sun goes down. UV rays accelerate chlorine loss, and chlorine consumption affects pH. By adjusting in the evening, you give chemicals all night to circulate and stabilize without the sun's interference.

I learned this lesson during a particularly hot summer when daytime adjustments never seemed to stick. Switching to evening applications cut my chemical usage by nearly 30% and improved overall stability.

Common Mistakes That Keep pH Low

The number one mistake? Overuse of trichlor tablets. These tablets are acidic by nature, constantly pushing pH downward. If you're using more than 2-3 tablets per week in a typical residential pool, you're fighting an uphill battle.

Another culprit is over-stabilization. When cyanuric acid levels exceed 100 ppm, it suppresses pH and makes adjustments less effective. I've seen pools where owners kept adding soda ash with no effect, only to discover their stabilizer was through the roof.

Poor alkalinity management also sabotages pH control. Think of alkalinity as pH's bodyguard – without adequate alkalinity (80-120 ppm), pH swings wildly with every addition of chemicals or swimmers. I always check and adjust alkalinity before tackling pH issues.

The Long Game: Preventing pH Drops

After two decades of pool care, I've learned that prevention beats correction every time. Regular testing – at least twice weekly during swim season – catches problems before they escalate. But testing is only useful if you act on the results immediately. pH problems compound quickly; what starts as a minor adjustment can become a major correction within days.

Consider your fill water too. If your tap water has low pH (common in areas with soft water), you're constantly fighting an uphill battle. I've installed simple calcite filters on garden hoses for clients with this issue. The water passes through crushed marble, naturally raising pH before it even enters the pool.

Equipment choices matter more than most realize. Salt chlorine generators tend to raise pH over time, while tablet feeders lower it. Understanding your equipment's tendencies helps you anticipate and prevent problems rather than constantly reacting to them.

When to Call It Quits and Start Fresh

Sometimes, despite your best efforts, water chemistry becomes so unbalanced that correction requires massive chemical additions. When I calculate that fixing the water will cost more than 50% of a drain and refill, I recommend starting fresh. It's not giving up – it's being smart about resources and time.

This particularly applies when dealing with high stabilizer, excessive dissolved solids, or persistent cloudiness alongside pH issues. Fresh water gives you a clean slate and often reveals underlying problems that were masked by chemical band-aids.

Final Thoughts from the Deep End

Managing pool pH isn't just about hitting numbers on a test kit. It's about understanding the interconnected nature of water chemistry and working with your pool's unique personality. Every pool has its quirks – some hold pH rock steady while others need constant attention.

The real secret to pH management is consistency and observation. Test regularly, adjust gradually, and pay attention to patterns. Your pool will tell you what it needs if you learn to listen. And remember, perfect water chemistry isn't about perfection – it's about maintaining a healthy range that keeps swimmers comfortable and equipment protected.

After all these years, I still get satisfaction from transforming problem pools into crystal-clear oases. There's something deeply satisfying about understanding and working with water chemistry rather than fighting against it. Master pH control, and you've conquered half the battle of pool maintenance.

Authoritative Sources:

Taylor Technologies. Pool & Spa Water Chemistry: A Testing and Treatment Guide. Taylor Technologies Inc., 2019.

Tamminen, Terry. The Ultimate Guide to Pool Maintenance. 3rd ed., McGraw-Hill, 2007.

Williams, Roy D. Complete Guide to Swimming Pool Care. Creative Homeowner, 2018.

National Swimming Pool Foundation. Pool & Spa Operator Handbook. National Swimming Pool Foundation, 2020.

Lowry, Robert W. Pool Chemistry for Service Pros. Lowry Consulting Group, 2016.