How do you lower the PH in a swimming pool?

Your local pool store should have pH decreaser.

Answerby buying a chemical called pH minus AnswerHi Aaron,

You can use the pH Minus product mentioned or you can go purchase some Muriatic Acid. Be careful using this as it does have a very strong odor and is harmful if breathed or stays on your skin too long. I've used both pH Minus and muriatic acid. My experience with pH Minus (a dry acid) is that it worked just fine in lowering my pH level. I've have good luck, and quick results, in lowering my pH levels and Total Alkalinity levels, which has been a very big problem for me this season thus far.

You want to maintain your pH levels at about 7.6 - 7.4 .

You can use muriatic acid. Just be careful as it's, obviously, acidic and will eat through 5 layers of skin before you can wash it off. Goggles, and rubber gloves for safety.

Also, run your pH between 7.6-7.8, not 7.4. The pH in water will naturally rise and when you get your alkalinity in range, about 80-100ppm, your pH should be locked in at 7.6-7.8. You'll need to use too much acid to keep your pool pH lower. Most "pool experts" say to run your pH around 7.2, and that's just plain wrong.

They get their info. from an index used by your local water treatment system, and not from an index specifically designed for pools.

Dry acid is about 4 times more expensive than muriatic acid. Chlorine is about 80% efficient at a pH of 7.2 and only 40% efficient at 7.8 meaning it takes twice as much chlorine at the higher pH to provide equal sanitation. Keep the Total Alkalinity at a minimum of 100ppm even if you have to add a little baking soda once in awhile, especially if you are using any dry or tablet form of stabilized chlorine (isocyanurates).