Additional clarifications on the Bicarb (or Positive CSI) Startup.
THE BEST PLASTER POOL START UP
How a startup program deals with and prevents the detrimental process of “plaster dust” forming in newly plaster pools is the key in helping to preserve a quality plaster finish that will last 20+ years.
Plaster “dust” is a calcium carbonate precipitate that often forms when filling new pools. Some people have been led to believe the release of calcium from new plaster (which forms the “dust”) is normal and cannot be prevented. That is incorrect. There is a start-up program that prevents plaster dust altogether by filling newly plastered pools with the right quality of positive Saturation Index (CSI) water and following one other simple step as explained below.
Understanding the Science of New Plaster
Water that is balanced with an CSI (or LSI) of 0.0 is good for cured pool plaster. However, that same balanced water is aggressive and detrimental to brand new plaster that is less than two to three weeks old, especially during the initial filling of new pools. This simple fact comes as a surprise to some who believe that perfectly balanced water (0.0 CSI) is always the goal. The reason for this is that about 20% – 25% of hardened plaster (cement) is a byproduct material known as calcium hydroxide. That compound is relatively soluble and dissolves in 0.0 CSI balanced water during the first 2 to 3 weeks which then leads to plaster dust formation and a compromised plaster surface. It is that dissolution process that causes the pH of the water to rise above 8.5 and creates a more porous plaster surface. The soluble calcium hydroxide is then converted (by CSI positive water) into insoluble calcium carbonate which precipitates and forms visible plaster dust.
The fortunate and good news is that filling pools with water that has an CSI of +0.5 or above prevents calcium hydroxide from being dissolved from the plaster in the first place. Since the calcium hydroxide remains in the plaster, it is then carbonated (converted) into a protective layer of denser and harder calcium carbonate surface intact. That is known as a “carbonation process” and takes about two to three weeks to be completed. When this startup is performed, the plaster surface is smoother and more stain-resistant than otherwise.
The Proper Startup Steps for Plaster Pools (Including quartz and pebble finishes).
[] Be Patient with new plaster: The first crucial step is to not fill the pool immediately after final troweling. Waiting a few hours (preferably four hours) to begin filling the pool will allow the fresh plaster in the deep-end bowl (which is troweled and finished last) to harden sufficiently before being submerged in water. Even positive CSI water will dissolve plaster material if it hasn’t been given enough time to hardened (hydrate) sufficiently.
[] Fill with the best water: Ensure that the fill water has an CSI of about +0.5 with a minimum alkalinity of 120 ppm. If the tap or fill water doesn’t meet this standard, which is often the case with tap water in this country, it will be too late to balance the water after it has filled the pool. The improper source water will have already done damage by dissolving many pounds of calcium from the plaster. No startup program will undo that damage after the fact.
After waiting a few hours, and once the specially balanced tap water begins to fill the pool, fill as quickly as safely possible. Any startup program that doesn’t require the two above conditions doesn’t provide the best care and protection for new plaster. As mentioned above, up to 40 pounds of calcium hydroxide can be dissolved and removed from plaster surfaces when the above steps are not followed. This is why many plaster finishes, including quartz and pebble, often become unsightly in the few months that follow due to greater porosity of the cement surface.
Research by onBalance indicates that that the fill water should have a “combined” total of alkalinity and calcium content of at least 400 ppm minimum (which essentially achieves the required CSI of about +0.5) to prevent the dissolution of calcium hydroxide from the plaster and the formation of plaster dust. (A combined total of 500 ppm is the ideal amount; 600 ppm is the maximum).
For example, if the fill water has an alkalinity of 80 ppm and 200 ppm of calcium hardness, raise the alkalinity of the fill water to 200 ppm (prior to using it to fill the pool) to achieve a combined total of 400 ppm (200 TA & 200 CH equals 400 ppm). Having an alkalinity above 120 ppm should provide adequate pH buffering and carbonation which helps prevent the pH from rising above 8.3.
When the above startup program is followed, there will be little or no plaster dust formation, the pH will be easier to keep and maintain below 8.2 and it will help retain a durable finish and preserve the vivid color in pigmented pool plaster. This is known as the Bicarb startup, which adds sodium bicarbonate to pre-condition the water and has been used successfully for over 40 years by many pool companies.
The Calcium Startup as Promoted by Orenda
The Calcium startup that Orenda Technologies promotes a good startup program. It also appropriately recommends waiting a few hours before starting the filling process along with adjusting the fill water to a positive CSI prior to entering the pool (similar to the Bicarb startup). The difference is that the Orenda program suggests raising the calcium hardness to a high level (by adding calcium chloride) to achieve a positive CSI instead of raising the alkalinity level.
[] A word of caution: The Calcium Startup is effective when the plaster quality is good. However, when the plaster quality is substandard, calcium hydroxide may bleed out, plaster dust may develop, and the pH of the water may rise above 8.3.
When the tap or fill water has a low alkalinity (less than 100 ppm), there may not be enough (pH) buffer strength to control and keep the pH down (below 8.3) when poor quality plaster results in some calcium hydroxide releasing into the water. We suggest that the fill water have an alkalinity above 120 ppm to aid in better carbonation and pH buffering.
[] A note about plaster quality: While it is true that a poor pool startup can ruin a high-quality plaster finish, especially an acid startup, it is equally true that poor quality pool plaster and workmanship will negate a good startup program, or in other words, a good startup process cannot fix bad plastering. Poor quality plaster and workmanship can result in the unpreventable loss of some calcium hydroxide and calcium chloride from the plaster regardless of the startup program. Any loss of plaster material results in greater plaster porosity and color fading.
In addition, poor quality plaster can result in excessive craze cracking, plaster turning whitish in streaks, spots and blotchiness, color fading, calcium nodules, and graying mottling of white plaster. Plastering mistakes that lead to these problems involve excessive water-to-cement ratio, excessive calcium chloride additive, excessive water troweling, and too early filling. A good startup program cannot prevent or alleviate those plaster mistakes, nor does aggressive water cause any of the above issues.
Poor chemical startups and poor long-term maintenance cause problems such as uniform calcium scaling or uniform etching throughout a pool, and localized damage where non-diluted chemicals come into direct contact with the plaster surface.
Good Tap water for Filling New Plaster Pools
In some areas of the country, the tap water already has a positive CSI with sufficient levels of alkalinity and calcium (combined total of at least 400+ ppm) and can be simply used, as is, to fill new plaster pools without having to do any chemical additions with bicarb or calcium. If that is the case, thank your lucky stars. There will be no need to do a special water compounding program. However, the only way to know is to, as we constantly emphasize, test the water before filling the pool.
Occasionally, the pH of the fill water may be higher than 8.4. If so, boric acid or regular muriatic acid can be added as part of the Bicarb startup process to lower and keep the pH below 8.3.
Here is a link to a research and scientific report on the beneficial effects of the Bicarb startup and comparison with two other startup methods.
THE BEST PLASTER POOL START UP
How a startup program deals with and prevents the detrimental process of “plaster dust” forming in newly plaster pools is the key in helping to preserve a quality plaster finish that will last 20+ years.
Plaster “dust” is a calcium carbonate precipitate that often forms when filling new pools. Some people have been led to believe the release of calcium from new plaster (which forms the “dust”) is normal and cannot be prevented. That is incorrect. There is a start-up program that prevents plaster dust altogether by filling newly plastered pools with the right quality of positive Saturation Index (CSI) water and following one other simple step as explained below.
Understanding the Science of New Plaster
Water that is balanced with an CSI (or LSI) of 0.0 is good for cured pool plaster. However, that same balanced water is aggressive and detrimental to brand new plaster that is less than two to three weeks old, especially during the initial filling of new pools. This simple fact comes as a surprise to some who believe that perfectly balanced water (0.0 CSI) is always the goal. The reason for this is that about 20% – 25% of hardened plaster (cement) is a byproduct material known as calcium hydroxide. That compound is relatively soluble and dissolves in 0.0 CSI balanced water during the first 2 to 3 weeks which then leads to plaster dust formation and a compromised plaster surface. It is that dissolution process that causes the pH of the water to rise above 8.5 and creates a more porous plaster surface. The soluble calcium hydroxide is then converted (by CSI positive water) into insoluble calcium carbonate which precipitates and forms visible plaster dust.
The fortunate and good news is that filling pools with water that has an CSI of +0.5 or above prevents calcium hydroxide from being dissolved from the plaster in the first place. Since the calcium hydroxide remains in the plaster, it is then carbonated (converted) into a protective layer of denser and harder calcium carbonate surface intact. That is known as a “carbonation process” and takes about two to three weeks to be completed. When this startup is performed, the plaster surface is smoother and more stain-resistant than otherwise.
The Proper Startup Steps for Plaster Pools (Including quartz and pebble finishes).
[] Be Patient with new plaster: The first crucial step is to not fill the pool immediately after final troweling. Waiting a few hours (preferably four hours) to begin filling the pool will allow the fresh plaster in the deep-end bowl (which is troweled and finished last) to harden sufficiently before being submerged in water. Even positive CSI water will dissolve plaster material if it hasn’t been given enough time to hardened (hydrate) sufficiently.
[] Fill with the best water: Ensure that the fill water has an CSI of about +0.5 with a minimum alkalinity of 120 ppm. If the tap or fill water doesn’t meet this standard, which is often the case with tap water in this country, it will be too late to balance the water after it has filled the pool. The improper source water will have already done damage by dissolving many pounds of calcium from the plaster. No startup program will undo that damage after the fact.
After waiting a few hours, and once the specially balanced tap water begins to fill the pool, fill as quickly as safely possible. Any startup program that doesn’t require the two above conditions doesn’t provide the best care and protection for new plaster. As mentioned above, up to 40 pounds of calcium hydroxide can be dissolved and removed from plaster surfaces when the above steps are not followed. This is why many plaster finishes, including quartz and pebble, often become unsightly in the few months that follow due to greater porosity of the cement surface.
Research by onBalance indicates that that the fill water should have a “combined” total of alkalinity and calcium content of at least 400 ppm minimum (which essentially achieves the required CSI of about +0.5) to prevent the dissolution of calcium hydroxide from the plaster and the formation of plaster dust. (A combined total of 500 ppm is the ideal amount; 600 ppm is the maximum).
For example, if the fill water has an alkalinity of 80 ppm and 200 ppm of calcium hardness, raise the alkalinity of the fill water to 200 ppm (prior to using it to fill the pool) to achieve a combined total of 400 ppm (200 TA & 200 CH equals 400 ppm). Having an alkalinity above 120 ppm should provide adequate pH buffering and carbonation which helps prevent the pH from rising above 8.3.
When the above startup program is followed, there will be little or no plaster dust formation, the pH will be easier to keep and maintain below 8.2 and it will help retain a durable finish and preserve the vivid color in pigmented pool plaster. This is known as the Bicarb startup, which adds sodium bicarbonate to pre-condition the water and has been used successfully for over 40 years by many pool companies.
The Calcium Startup as Promoted by Orenda
The Calcium startup that Orenda Technologies promotes a good startup program. It also appropriately recommends waiting a few hours before starting the filling process along with adjusting the fill water to a positive CSI prior to entering the pool (similar to the Bicarb startup). The difference is that the Orenda program suggests raising the calcium hardness to a high level (by adding calcium chloride) to achieve a positive CSI instead of raising the alkalinity level.
[] A word of caution: The Calcium Startup is effective when the plaster quality is good. However, when the plaster quality is substandard, calcium hydroxide may bleed out, plaster dust may develop, and the pH of the water may rise above 8.3.
When the tap or fill water has a low alkalinity (less than 100 ppm), there may not be enough (pH) buffer strength to control and keep the pH down (below 8.3) when poor quality plaster results in some calcium hydroxide releasing into the water. We suggest that the fill water have an alkalinity above 120 ppm to aid in better carbonation and pH buffering.
[] A note about plaster quality: While it is true that a poor pool startup can ruin a high-quality plaster finish, especially an acid startup, it is equally true that poor quality pool plaster and workmanship will negate a good startup program, or in other words, a good startup process cannot fix bad plastering. Poor quality plaster and workmanship can result in the unpreventable loss of some calcium hydroxide and calcium chloride from the plaster regardless of the startup program. Any loss of plaster material results in greater plaster porosity and color fading.
In addition, poor quality plaster can result in excessive craze cracking, plaster turning whitish in streaks, spots and blotchiness, color fading, calcium nodules, and graying mottling of white plaster. Plastering mistakes that lead to these problems involve excessive water-to-cement ratio, excessive calcium chloride additive, excessive water troweling, and too early filling. A good startup program cannot prevent or alleviate those plaster mistakes, nor does aggressive water cause any of the above issues.
Poor chemical startups and poor long-term maintenance cause problems such as uniform calcium scaling or uniform etching throughout a pool, and localized damage where non-diluted chemicals come into direct contact with the plaster surface.
Good Tap water for Filling New Plaster Pools
In some areas of the country, the tap water already has a positive CSI with sufficient levels of alkalinity and calcium (combined total of at least 400+ ppm) and can be simply used, as is, to fill new plaster pools without having to do any chemical additions with bicarb or calcium. If that is the case, thank your lucky stars. There will be no need to do a special water compounding program. However, the only way to know is to, as we constantly emphasize, test the water before filling the pool.
Occasionally, the pH of the fill water may be higher than 8.4. If so, boric acid or regular muriatic acid can be added as part of the Bicarb startup process to lower and keep the pH below 8.3.
Here is a link to a research and scientific report on the beneficial effects of the Bicarb startup and comparison with two other startup methods.
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