Domakihub How to Raise Pool pH: A Simple Step-by-Step Guide
Fix low, acidic pool water and protect swimmers, surfaces, and equipment.
Reviewed by Domakihub pool pros · 2026-06-23 · 5 min read
Low pH leaves pool water acidic, which stings eyes, corrodes metal fittings, and eats away at plaster, grout, and liners. The video above shows the process in action, and this guide breaks it into clear steps you can follow. Whether you manage a family home, a holiday rental, or a hotel pool in Greece, getting pH back into range keeps the water safe, clear, and comfortable.
Why pool pH matters
pH measures how acidic or basic your water is, on a scale from 0 to 14. For swimming pools the target range is 7.2 to 7.8, with around 7.4 to 7.6 being ideal. When pH drops below 7.2 the water turns acidic and starts to attack everything it touches: it corrodes ladders, handrails, heaters, and pump seals, etches plaster and tile grout, and can wrinkle or bleach a vinyl liner.
Acidic water is also uncomfortable for swimmers, causing red, irritated eyes and dry, itchy skin. On top of that, low pH makes chlorine burn off faster, so you spend more on sanitiser while still getting weaker protection. For a busy rental or hotel pool in the Greek summer, that combination quickly becomes expensive and reflects badly on guests' experience.
What causes pH to drop
pH naturally drifts down over time. Heavy use, rain, top-up water, and certain chemicals all push it lower. The biggest culprit is usually acidic chlorine products such as trichlor tablets, which slowly drag pH and alkalinity down as they dissolve. Frequent acid additions to control scaling can also overshoot and leave the water too acidic.
Because low pH often travels together with low total alkalinity, it helps to test both before treating. Alkalinity acts as a buffer that keeps pH stable, so a pool that keeps sliding acidic frequently needs its alkalinity corrected too. Knowing which one is off tells you which product to reach for.
Steps to raise your pool pH
- 1
Test the water first
Use a reliable test kit or test strips to check pH and total alkalinity. Confirm the pH is genuinely below 7.2 before adding anything. Note both readings, because the right product depends on whether only pH is low or alkalinity is low as well. Test in the morning before the day heats up for the most representative result.
- 2
Choose the right chemical
To raise pH without significantly affecting alkalinity, use soda ash (sodium carbonate), often sold as pH increaser or pH Up. If your alkalinity is also low, baking soda (sodium bicarbonate) raises alkalinity and nudges pH up at the same time. For small corrections, soda ash is the go-to; reserve baking soda for when both numbers need lifting.
- 3
Calculate the dose
Read the product label for the dose per cubic metre or per 10,000 litres of water, and work from your pool's actual volume. A common rule of thumb is roughly 150 grams of soda ash per 50 cubic metres to lift pH by about 0.2. Add conservatively: it is far easier to add more later than to fix an overshoot.
- 4
Add it with the pump running
Pre-dissolve the soda ash in a bucket of pool water, then pour the solution slowly around the perimeter of the deep end while the circulation pump runs. Keeping the water moving spreads the chemical evenly and prevents cloudy clumps or surface scaling. Wear gloves and eye protection, and add chemicals to water, never water to chemicals.
- 5
Wait, retest, and adjust
Let the pump circulate for at least 4 to 6 hours, then retest pH and alkalinity. If pH is still below 7.2, repeat with a smaller dose and retest again. Once you are in the 7.4 to 7.6 range, the job is done. Keep testing two to three times a week through the swimming season to catch drift early.
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FAQ
- Can I use baking soda instead of soda ash to raise pH?
- You can, but they do different jobs. Soda ash (sodium carbonate) raises pH strongly with little effect on alkalinity, making it ideal when only pH is low. Baking soda (sodium bicarbonate) mainly raises total alkalinity and only nudges pH up a little, so use it when both readings are low. Test first to decide which one your pool actually needs.
- How long after raising pH can people swim?
- Run the pump for at least 4 to 6 hours to fully circulate the chemical, then retest. Once pH reads between 7.2 and 7.8 and the water is clear, it is safe to swim. If you added a large dose, waiting until the next retest confirms a stable reading is the safest approach, especially for rental and hotel pools.
- My pH keeps dropping no matter what I do. Why?
- Persistently low pH usually points to low total alkalinity, which normally buffers pH and keeps it stable. Raise alkalinity into the 80 to 120 ppm range with baking soda first, and pH will hold much better. Acidic chlorine tablets and frequent acid dosing also drag pH down, so review your sanitiser and chemical routine.