07/17/2026
THE IMPORTANCE OF NEW PLASTER START-UPS
The importance of a proper and immediate start-up of a newly plastered swimming pool cannot be overstated. But before we get into the how, we must understand the why. When fresh untreated water is introduced into a newly plastered swimming pool, there are immediate reactions between the water and the plaster as the water seeks equilibrium. This means the water will seek out plaster constituents to satisfy its desires. Plaster is inherently rich in soluble calcium products and water is the universal solvent so it will immediately begin drawing calcium products out of the new plaster, thus ultimately changing the plaster, and making it more porous. As this process proceeds, the pH. dramatically increases to levels sometimes more than 10! As this happens, the water is now oversaturated and cannot keep all the dissolved calcium in solution and the calcium precipitates out into what is commonly called plaster dust.
Ideally, we would like to have no plaster dust occur in a newly plastered pool. It is generally accepted that the first 28 days of the curing period is key. In a best-case scenario, we would want to be able to treat the water before it goes into the pool and has a chance to interact with the new plaster. There are a couple of different processes that are well known that help to accomplish this and they are both viable options. One is called the Bicarb start-up and the other is the Orenda start-up. First thing I like to do is get the filtration system up and running to ensure we have filtration and circulation. I recommend continuous filtration for at least the first 3-5 days. Before starting either process, testing the fill water is done and calculations are made to determine how much of the needed chemicals are required. Both involve setting up a pre-treatment barrel to which chemicals are added and the fill water flows through this vessel and chemicals then into the pool. The chemicals in the barrel give the water what it desires so it will not draw it out of the plaster. A stain and scale inhibitor chemical should also be introduced via this method. The mechanics of the Bicarb start-up can be found at http://www.poolhelp.com/home/onbalance-research/education/the-bicarb-start/the-mechanics-of-the-bicarb-start/, and the Orenda start-up can be found at https://info.orendatech.com/the-orenda-startup.
The previous paragraph addresses the best-case scenario where we can be on site and pre-treat the water before it enters the pool. That is not always possible in today’s busy world. Often the pool is already full by the time the start-up is to take place. If this is what you must work with you can always follow the National Plaster’s Council (NPC) start-up program. You cand find it by visiting www.NPConline.org. Here is another option that one can use. I always suggest starting the filtration system before beginning any work on the start-up. I suggest that it should run continuously for the first 3-5 days or until all the plaster dust is removed from the pool. This way we ensure that the system is operational. If it is not, I will usually not proceed. In this case, one should always fully test and document the fill water and retain in your records. Next, do a complete test of the already filled pool’s water. You will likely see an increase in the calcium hardness and pH. and often the total alkalinity as well. This is due to the water’s immediate interaction with the new plaster. Before adding any other chemicals, add a good stain and scale inhibitor according to manufacturers directions. The next step should be to adjust the total alkalinity into the proper range. Always address the total alkalinity first as it has a bearing on the adjustment of the pH., which is the next component to address. The timing of these first three chemical additions can occur in close succession to one another. That is usually the end of my first day steps, unless I can make another trip later in the day after several hours have passed. The pool surface should be brushed 2-3 times daily at this point until all the plaster dust has been removed. On the second visit, we again start with a full battery of pool water tests. If we were successful on the first visit, our alkalinity and pH. are now in the proper range. On freshly plastered pools, the pH. will have a tendency to want to climb so we want to always push it down to the lower end of the acceptable range. If we need to add more acid to lower the pH. that is the next step. After that we want to increase the calcium hardness to a minimum of 200 parts per million (ppm). That is all for the second visit. Visit three should occur the following day and at this point we are trying to maintain all the parameters in their proper ranges. We can now add a small amount of cyanuric acid if desired to 20-30 ppm. I generally like to wait until day 4-5 before adding any chlorine when conditions allow.
I hope this article gives you a better understanding of the why we need to do this and provides you with options for start-ups that may suit your needs. All of these options should include routine follow-ups throughout the first 28 days to ensure that the water remains within the proper ranges.
The onBalance Method of Starting Up New Plaster Pools With More Durable Surfaces and Without Plaster Dust Step 1 – Pre-testing the Water We Test the chemistry of the tap water that will be used to fill the pool. The key characteristics we observe are pH, Alkalinity, Hardness, Copper and Iron. Step...
