How do you change the alkalinity in your inground pool?

Answer 1

The best way to lower the alkalinity in your pool depends on which chemicals you have on hand. If you have muriatic (HCl Buame) acid on hand for lowering the pH, carefully pour in about 1 gallon per 10,000 gallons of pool water. If you have sodium bicarbonate on hand (normally used for treating alkalinity), dump in about 1 pound per 10,000 gallons of pool water. Both of these chemicals will lower the pH of the water. Muriatic acid will obviously lower the pH because you're mixing an acid into already acidic water [solution] (sodium hypochlorite [aka liquid chlorine] + water = HCl). Sodium bicarbonate reacts with the water to form sulfuric acid (H2SO4). You may have to add a strong base to increase the pH a little bit after adding so much acid. The ideal pH of a pool is 7.2-7.6. This will help keep any fixtures in the pool and the lining of the pool safe from corrosion.

You want to run your pool water alkalinity level between 80-100ppm, not up to 150 as some may suggest. Most pools guys get their info. on how to balance pools from your local water company. Yes, this is correct. It's called the Langelier Index, which was originally designed for public water systems. This index was never intended for pools.

In the 1950's, when pools started to come into the mainstream, this was the only index available, so it was used to balance pools and hot tubs.

The Hamilton Index, which I use, is much more pool-friendly and is specifically designed for pools. It takes into consideration acid rain, drag-off, heat, the sun, organic and inorganic matter in the pool, etc...

While I don't completely agree with the Hamilton Index, it is much closer to how a pool should be balanced and will save you much time and money in

the long run.

To raise the alkalinity in Swimming Pools, the most common and the safest chemical is Sodium Bicarbonate. You know, good ole' fashion Arm and Hammer Baking Soda.

Try to not add more than 2lbs. of Sodium Bicarbonate, or another kind of alkalinity increaser, for every 10,000 gallons of water in a single application.

While your filtration system is off and the water is motionless, stand in the deep end of the pool and sprinkle (don't dump the product or go too fast), the Sodium Bicarbonate

or alkalinity up.

Allow the water to sit for 2-3 hours, then turn the pump back on and allow the pool to fully circulate, usually 4-6 hours, then re-test your pool's alkalinity balance. Doing this technique will increase your alkalinity without much happening to the pH level.

Using the proper chemicals and proper techniques will allow for better results. pH is 7.6-7.8, not 7.2. Too low and you'll use too much acid to keep it there.

Lower Alk.

While your filtration system is off and the water is motionless, stand in the deep end and slowly add (don't dump the product or go too fast), the pool acid, or alkalinity minus if you wish, into the pool. Please remember to use goggles and heavy rubber gloves.

If you spill any acid on your skin, it will probably eat through 3 layers of skin before you can wash it off. Remember, safety first.