WATER
CHEMISTRY

Balanced water chemistry is vital to maintaining not only the appearance of your pool, but its durability and life-span, as well. Bad water chemistry can destroy your investment and void your warranty. Prevent potential problems such as mineral scale and metal stain formation, cloudy water, or deterioration of the interior finish and the equipment by testing your water regularly.

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Proper start-up and maintenance of your freshly plastered pool is important. And "pool maintenance is more than simply adding sanitizer, adjusting the pH and running a filter."

Info provided courtesy of the https://www.nationalplastererscouncil.com/water-chemistry/

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EFFECTS OF BAD WATER CHEMISTRY

There are Five Factors that affect water quality: pH, total alkalinity (adjusted to carbonate alkalinity), calcium hardness, total dissolved solids, and sanitizer. In a nutshell, it's your pools pH, carbonate alkalinity, calcium hardness, total dissolved solids, and temperature of the water that is used to determine your pool's water balance. By monitoring and adjusting these specific aspects of your pools water chemistry you can keep the water balanced, avoiding the dreaded “scale” and "corrosion" that plagues pool owners everywhere. Scaling is most often related to high pH, or elevated levels of alkalinity, calcium hardness, total dissolved solids, or a combination of these. Corrosion and deterioration on the other hands is related to low pH, or low levels of carbonate alkalinity, calcium hardness, total dissolved solids, or a combination of these. Low pH can e water can destroy pool tile grout, metal light rings, heaters, and pool equipment.

PREVENTION

Maintaining proper service and proper water balance (chemical levels or ‘ranges’) is essential in the prevention of these issues. Water chemistry should be maintained in accordance with APSP ‘Balanced Conditions’. The following parameters are recommended: pH should be kept within the range of 7.2 – 7.8. At a pH below 7.2, the water is considered to be ‘aggressive’, and a pH above 7.8 is considered to be ‘scaling’, and has the tendency to precipitate minerals and/or metal causing scaling or staining of the surface. Carbonate Alkalinity should be kept within the range of 80 – 120 ppm. To Adjust Alkalinity: Increase: 1.5 pounds of Alkalinity Increaser or Sodium Bicarbonate will increase the total alkalinity of 10,000 gallons of pool water by 10 ppm. Decrease: Add small amounts of liquid or dry acid (diluted or dissolved) once each day until desired level is reached. In general, about 2 pounds of dry acid will reduce total alkalinity of 10,000 gallons of pool water by 10 ppm. For minor adjustments, do not add more than one pound of dry or one pint of liquid to 10,000 gallons of water per day. Remember, do not add ANY acid if pH is less than 7.2.To reduce total alkalinity, add small amounts of acid, either liquid or dry (dissolved in a bucket of water), over a period of several days instead of making significant adjustments rapidly.
Calcium Hardness content should be kept within the range of 200 – 400 ppm . A low calcium hardness level can cause the deterioration of the interior finish and tile grout. To increase calcium hardness, add calcium chloride. One pound of calcium chloride will increase the calcium hardness of 10,000 gallons of water by 10 ppm. Total Dissolved Solids should not exceed 1500 ppm (above the source water TDS). If higher than 1500 ppm, the water has the tendency to precipitate minerals and/or metal causing scaling or staining of the surface For salt water pools, the TDS should not exceed 1500 ppm above the source water TDS plus the added salt. The water can also become cloudy. It is recommended to drain some of the water and replace with fresh water. Alternatively, in certain regions of draught or water restrictions, there are methods to reduce or remove metals, minerals, and dissolved solids through filtration.Cyanuric Acid should be kept within the range of 30 – 50 ppm. It is recommended to periodically drain some of the water and replace with fresh water, so that cyanuric acid levels do not build up.

ph Levels

pH refers to the level of activity of an acid or base in the water and is the most critical chemical factor in swimming pools It is measured on a scale from 0-14 with 7 being neutral. If you have a pH value between 0-7, this is considered acidic. A pH value of 7-14 is considered alkaline with 14 being the greatest base activity. Your pool water is best kept in the range of 7.2-7.8. If below 7.2 the water is considered to be corrosive and a pH higher than 7.8 will increase the tendency for cloudy water.

Changes in the pH are caused by many factors, but the most common is the sanitizer used. Standardly chlorine is used in pools, and it comes in a variety of forms. For example, most tableted forms of chlorine have a very low pH and will tend to lower pH over time, while liquid chlorine is very high in pH and will tend to raise pH values. A quality professional can work with you in understanding what types of sanitizer are best for your pool.

Total Alkalinity

Total alkalinity is the ability of your pool water to resist a change in pH. The purpose is to help manage or control the pH in the pool. Total alkalinity acts as a buffer so when materials are added to a pool that would cause the pH to go up or down; the changes are controlled in order to prevent damages to your pool water balance. Remember that total alkalinity is best within the range of 80-120 ppm. When less than 80 ppm the water is considered aggressive, and the pH can quickly increase or decrease. If higher than 120 ppm, the water can become cloudy and scale forming with the pH increasing. To reduce total alkalinity, add small amounts of acid, either liquid or dry, over a period of several days instead of making significant adjustments rapidly.

To Adjust Alkalinity:

Increase: 1.5 pounds of Alkalinity Increaser or Sodium Bicarbonate will increase the total alkalinity of 10,000 gallons of pool water by 10 ppm. TO

Decrease: Add small amounts of liquid or dry acid once each day until desired level is reached. In general, about 2 pounds of dry acid will reduce total alkalinity of 10,000 gallons of pool water by 10 ppm. For minor adjustments, do not add more than one pound of dry or one pint of liquid to 10,000 gallons of water per day. Remember, do not add ANY acid if pH is less than 7.2.

Calcium Hardness

Calcium hardness refers to the sum of all the calcium dissolved in water. Having very high levels of calcium can be unstable and even more unstable if the pH or the total alkalinity rise above the normal levels. This can result in cloudy water and/or scale. Soft or low calcium water is considered aggressive and can remove calcium from plaster. If the pool is vinyl or fiberglass, the low calcium water may attack metal fittings and heat exchangers. This attack can result in the destruction of the fittings or pinhole leaks in the heater. When corrosion occurs, stains to appear on pool surfaces. Calcium content is best in the range of 200-400 ppm.

How to increase calcium hardness:

To increase calcium hardness, add calcium chloride. One pound of calcium chloride will increase the calcium hardness of 10,000 gallons of water by 10 ppm.

Total Dissolved Solids

Total dissolved solids (TDS), is a lesser issue in fresh water, but pool water that has not been replaced over time, can accumulate TDS. TDS is essentially the sum of all materials dissolved in the water and normally run in the range of 250 ppm and higher. In general, when the TDS exceeds approximately 1500 ppm, problems may begin to occur. TDS can result in cloudy or hazy water at an elevated level. Therefore, it can be difficult in maintaining water balance, the reduction in sanitizer activity, and foaming. To reduce TDS, you need to drain some of the water and replace with fresh water. Unfortunately, sequestering agents do not help when high TDS levels are causing cloudy pool water.

National Plasters Council

Florida Pool Finish is proud to be a member of the National Plaster's Counsel. NPC provides the most up to date standards in the pool plaster industry.

NPC MISSION:

The National Plasterers Council will continue to be the utmost authority in the preparation, application, materials, start-ups and preservation of cementitious pool interior finishes. The NPC will collaborate with other associations and serve the industry through research, education, promotion, and certification of all segments of the pool industry including pool owners, the pool service providers, plasterers, manufacturers, specifiers, remodelers, architects, and builders.

National Plasters Council is a trade association for pool plasterers that originated from the vision to “provide a voice and support for swimming pool plasterers.” We give a voice to one industry and provide the research and expertise for those whose products or services related to the pool resurfacing industry.

Since its formation in 1988, the Council has been focused on studying plaster surface problems and the writing of technically sound practices for the industry. Pool surface research has been one of the primary focuses of NPC and we have a very strong foundation and vision which will take the association to new levels now and in the future.

If you are looking for a swimming pool professional whether for building or pool resurfacing, we can help connect you with applicators, builders, manufacturers and other tradesmen who participate in the swimming pool construction and pool resurfacing fields. Those part of the NPC are provided with the knowledge and authority to be leaders in the industry and stay on top of what is cutting edge in the industry.

Affiliations

American Shotcrete Association
Independent Pool and Service Association
California Pool and Spa Association
The Association for Pool and Spa Professionals
American Concrete Institute
American National Standards Institute
Institute for Code Council