6 Steps to Rebalance Your Pool After a Water Change

Test everything from scratch The fresh water diluted all chemical levels, so do not assume anything is still balanced. Test pH, alkalinity, chlorine (free and total), stabilizer (CYA), and calcium hardness.

Calculate the percentage drop If you replaced 30% of the water, all levels are roughly 70% of what they were. Add roughly 30% of your normal dose to get back to target ranges.

Check stabilizer and calcium hardness Stabilizer is easily overlooked if you use chlorine tablets, and it is hard to fix later. Calcium hardness matters most for plaster pools, but test it for any pool.

Top up salt if you have a salt system Salt levels drop by the same percentage as the water you added. Add enough to restore the correct concentration.

Shock the pool if you added a lot of water at once Large water additions can stir up sediment or old pipe debris. Shocking kills anything that might have been introduced.

Adjust chemicals in the right order Start with alkalinity, then pH, then chlorine or shock, then everything else. Wait a few hours between each adjustment.