*Depends on the local fill water. Normally, 500 ppm is the maximum.
Low pH will cause:
· Etched Plaster
· Stained Plaster
· Eye & Skin Irritation
Destruction of Total High pH will cause:
· Scale Formation
· Cloudy Water
· Short Filter Runs
· Eye & Skin Irritation
· Poor Chlorine Efficiency
Even though water with a pH of 7.0 is “neutral,” it is not advisable or acceptable to keep pool water at this pH. The water is aggressive or corrosive to plaster and metals, it will cause stains, it will cause eye and skin irritation, and it will lower total alkalinity. Experts generally agree that the absolute ideal pH for swimming pool water is 7.5 -although the Minimum is 7.2, the Ideal Range is 7.4 to 7.6 and the maximum is 7.8. pH and total alkalinity are related. Acid and some other acidic pool chemicals lower pH. Soda ash, sodium bicarbonate and other basic pool chemicals raise pH. pH can be changed easily or with difficulty. pH can be changed rapidly or slowly. Total alkalinity determines the speed and ease of pH change.
Raising pH & Total Alkalinity
To raise total alkalinity and pH, you will use PH Up (Soda Ash) or Alkalinity Up (Sodium Bicarbonate). Each one affects pH and total alkalinity differently.
· Soda Ash is the strongest. It has a pH of 13 and it adds to the total alkalinity. Use soda ash when you want to raise total alkalinity and pH. Adding 6 ounces of soda ash to 10,000 gallons of water will raise the pH by approximately 0.2. The same 6 ounces will also raise the total alkalinity of 10,000 gallons of water by about 2 ppm. Do not add more than 4 pounds per 10,000 gallons at any one time or on the same day that Hardness Plus is added. Wait 4 hours and retest. Add more if needed.
· Alkalinity Up (Sodium Bicarbonate) is also called baking soda. It has a pH of only 8.3. It contributes to total alkalinity more than soda ash does. Use sodium bicarb when you need to raise total alkalinity without changing the pH very much. Adding 11⁄2 pounds of sodium bicarb to 10,000 gallons of water will increase total alkalinity by 10 ppm with only a slight change in pH. Do not add more than 10 pounds per 10,000 gallons at any one time or on the same day that Hardness Plus is added. Wait 4 hours and retest. Add more if needed.
Lowering pH & Total Alkalinity To lower total alkalinity and pH, you will use either liquid (muriatic) acid or Dry Acid. They both have the same effect on total alkalinity and pH. The choice is whether you want to buy, store and handle dry or liquid acid. The dry acid is a little safer.
NOTE: 21⁄2 lbs. of dry acid equals 1 quart of muriatic (liquid acid).
· First, adjust the total alkalinity. The proper range for total alkalinity depends upon the type of pool. The proper range for a gunite (plaster) pool is 80-120 ppm. The proper range for a vinyl liner, painted or fiberglass pool is 100-140 ppm. If the total alkalinity is higher than 120 ppm (plaster pool) or 140 ppm (vinyl liner pools), acid should be added to lower it. Adding 21 fluid ounces of liquid (muriatic) acid or 11⁄2 pounds of Dry Acid to 10,000 gallons of water will lower total alkalinity by 10 ppm.
· The Dry Acid should be predissolved in a bucket of water. If muriatic acid is to be used in a vinyl-lined, fiberglass or painted pool, it must first be prediluted in water. Always add acid to water. Calculate the total amount of acid needed using the above information. Then, add acid a little at a time – no more than 16 fluid ounces of liquid acid or 20 ounces of dry acid (predissolved in water) per 10,000 gallons of pool water.
· Pour the acid or acid solution into the pool water while walking around the pool. Be careful not to pour acid into the skimmer, near underwater lights, near steps or near ladders.
· Water may be retested and additional acid added after 4 hours of circulation.
Do not try to attain the proper alkalinity with one single slug of acid.
Do not add acid more than 3 times in one day.
Always test the water before each addition of acid to make sure that acid is still needed.
Follow all label directions. Do not add more than 16 fluid ounces of muriatic acid or 20 ounces of dry acid per 10,000 gallons at any one time. Wait 4 hours and retest. Add more if needed.
Once total alkalinity is in the proper range (proper ranges are listed above), the pH should then be adjusted to the 7.4-7.6 range.
If the pH is now lower than 7.4
Soda Ash must be added to raise it to the proper range. Add 6 oz. of soda ash per 10,000 gallons of water. Soda ash may be added directly to the water. Water should be re-tested in 4 hours and additional soda ash added if the pH is lower than 7.4.