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Protecting Plaster: The First 28 Days
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Protecting Plaster: The First 28 Days

Pool start-ups have long been recognized as a key phase where the construction process gives way to service, a time where the curing process is crucial to the appearance and longevity of pool plaster, and by dent also critical to keeping customers happy with the appearance of their new pool.

By Alicia Stephens

As builders quickly install pools to keep pace with the current demand, it is important to refresh staff on the steps needed to protect plaster pool surfaces during the first 28 days. The procedures and products used during this period are crucial to protecting the surface, ensuring against staining, and supporting the plaster curing process for long-term integrity.

When discussing any pool care maintenance program, including start-ups and weekly maintenance, protecting the plaster surface is key to keeping new pool owners happy. The goal is to start-up and balance the pool water in a way which protects the surface from damage and protects the investment the homeowner has made in the pool.


Using best-practice start-up procedures will also provide balanced, sanitized water which will protect the swimmer as well as provide the ideal swimming environment.

It may seem intuitive, but it is important to include every step of the process in a plaster start-up checklist. For example, before filling the pool with water, the filtration system should be hooked up, ready to run, and turned on as soon as the water is at an appropriate level. Taking a minute to aim the returns down towards the bottom of the pool and pointing them to the right allows the jets to maximize water circulation.

If there is a heater on the pool, it should not be turned on until all plaster dust has been eliminated. Scale damage can occur within the heater if it is turned on too early. In addition, wheeled devices such as plaster vacuum heads must not be used for the first 28 days to prevent damage from the wheels on the pool’s surface.

Finally, the pump should run continuously for the first 72 hours once the pool is full. After 72 hours, the run time can be reduced to 10 to 12 hours per day, although 24 hours is always ideal.

In addition to these steps, there are some specific actions which should be taken on Days 1 through 28 after the plaster is completed.

Day 1

When filling an empty pool, it is a good idea to test the source water to determine what to expect when the pool is full. The balance parameters of the source water will indicate what needs to be addressed first. A test for metals should also be done to identify potential staining and discolouration issues, allowing treatment to occur before the surface is damaged. If metals are in the source water, the ideal approach is to use a pre-filter on the fill hose to remove them before they enter the pool.

A pre-filter is attached to the hose supplying the source water to the pool. There are several different options, but each one contains technology aimed at removing metals from the source water before they reach the pool. If a pre-filter is not used and substantial levels of metals are present, oxidizing and balancing the water can easily lead to discolouration and surface staining. This will result in the need to follow a complete stain and metal removal process to return the pool to the expected condition.

Once the water covers the entire bottom of the pool, adding a scale prevention start-up product will be beneficial. These products help minimize plaster dust by chelating and sequestering the particles released as part of the curing process. They can also reduce the amount of brushing required for the new surface.

When the pool is completely full, the circulation and filtration system should run continuously for the first 72 hours. The water must also be tested for pH and total alkalinity (TA) and adjusted as needed to maintain the desired range. The total alkalinity should be 80 parts per million (ppm). If it is higher than this, pre-diluted muriatic acid may be added to lower it. The acceptable pH range is 7.2 to 7.6.

Achieving and maintaining this range is vital for the protection of the pool’s surface. High pH can lead to scale and metal staining, which can cause extensive damage to the new pool’s surface.

Day 2

On Day 2 of a new pool start-up, the pump and filter should still be running continuously. Starting today, the pool will need to be brushed twice daily until the plaster dust dissipates completely. Both the pH and total alkalinity should be tested and adjusted as needed to maintain the ideal readings. Finally, the calcium hardness reading must be taken and adjusted to 150 ppm. If the calcium hardness is low, calcium chloride can be added in 4.6 kg (10 lbs) increments in the morning and afternoon, until the desired level of calcium hardness is achieved.

Day 3

By Day 3, the water balance parameters should become more stable. It is the last day for the pump and filter to run continuously. The surface must continue to be brushed to help eliminate plaster dust, and the total alkalinity and pH can be tested and adjusted as needed. At this point in the start-up process, it is time to add sanitizer.

This step is initiated by slowly adding chlorine to edges of the pool while the pump is running. Calcium hypochlorite can be pre-dissolved at a ratio of 0.45 kg (1 lbs) of product per 11.3 L (3 gal) of water. Sodium dichloroisocyanurate (dichlor) or liquid chlorine can be added directly to pool water. Trichloroisocyanuric acid (trichlor) sticks or tabs can be added to the skimmer or feeder at any time.

Using a floating chlorinator at this stage is not recommended. As the product inside dissolves, it releases high concentrations of chlorine with low pH. If the floater becomes trapped against the surface of a new plaster pool, it can ‘scorch’ the surface as the product dissolves. Avoiding the use of floaters for the first 28 days helps prevent damage which can occur if a floater comes in contact with a new surface.

Finally, if the pool uses a chlorine generator, salt should not be added for the first 28 days, as surface damage can occur. The pool must be chlorinated as outlined above for the first month before switching over to the chlorine generator.

Day 4

On Day 4, the pump’s run time can be reduced to 10 to 12 hours per day, although continuing to run it for 24 hours is ideal. If needed, the surface can be brushed to remove plaster dust. Chlorine residual, pH, and total alkalinity should be tested and adjusted as needed. The calcium hardness can also be adjusted, but it should never exceed 200 ppm for any reason. The final step for the day is to add stabilizer, to establish a cyanuric acid (CYA) residual of 30 to 40 ppm.

Also known as conditioner, CYA is vital to protecting free chlorine from the sun’s ultraviolet (UV) rays. It can be added to the pool as a slow-dissolving granular product or as a liquid. While both are effective, the granular product is often hard to apply due to its slow-dissolving nature. If CYA granules are broadcast into the pool and do not dissolve quickly, damage can occur to the pool’s surface. Using liquid CYA helps reduce the chance of surface damage.

Days 5 to 28

Days 5 to 28 are essentially the same routine. Water balance parameters can be tested and adjusted as needed, and the surface should be brushed as necessary to loosen plaster dust. On Day 7, any remaining plaster dust can be vacuumed from the pool. A routine stain and scale control product should be added to protect the finish and equipment from metal-based staining and calcium-based scale buildup. This product will then be added monthly as part of routine maintenance, in order to extend surface and equipment protection.

Day 29

On Day 29, the curing process is complete, and the pool can be switched to a routine maintenance program. If it is a salt pool, salt can be added at this time to attain the desired residual set by the salt cell manufacturer. Once the salt is added, the chlorine generator may be turned on and salt pool maintenance will begin. Checking and balancing the pH is vital, as salt pool chemistry contributes to an overall rise in pH.

It is important to wait until Day 29 to start the pool on salt, to prevent surface damage. The pool can be maintained with the manual addition of chlorine via feeder, skimmer, or direct application until the curing process is complete and salt can be added.


Taking the previously outlined steps during its first 28 days will set the stage for a long, successful, and trouble-free life for a plaster pool. Water balance is critically important to preventing surface damage, and it must be tested and adjusted daily during the curing process. Finally, using appropriate chemicals at the start-up—rather than reacting to issues as they arise—will allow staff to be proactive in caring for each new pool.

Alicia Stephens is the education and training manager for Biolab Inc. In her 20 years with the company, she has focused primarily on education, training, and development, as well as technical support and new product research and integration. Currently, Stephens supports all education and training initiatives for the Biolab Pro Dealer division. She can be reached via email at [email protected].

Photo by Andy Dean Photography | Shutterstock

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