The Science Behind Calcium Nodules and How They Can Affect Your Pool

As many pool owners will tell you, there are a number of pool maintenance tasks that will need to be performed by Dallas/Fort Worth pool professionals, but one development that befuddles many homeowners is the presence of calcium nodules. What often looks like bird droppings is an unsightly development and is common in many replastered pools.

What are calcium nodules?
According to the Pool Genius Network, calcium nodules are small mounds or piles of calcium carbonate that can seep out of plastered portions of a pool over time. Typically, the most common calcium nodules are caused by delamination, or a void between the plaster and its substrate. If the pool experiences a bond failure such as an air cavity, this can eventually cause the plaster to crack and allow calcium hydroxide to bleed into the water. As the calcium comes in contact with alkaline pool water, this will create a byproduct of calcium carbonate that will result in the nodules appearing along the surface of the pool.

What can be done about them?
Ultimately, the appearance of nodules depends on the quality of the plastering job done on the pool, as technicians will need to avoid weak bonds between the plaster and subsurface. Other risk factors that could contribute to nodule development is allowing the plaster to dry too quickly before the pool is filled with water, as well as small cracks and dings that form on pool walls as the result of regular use, reported If the job is done right the first time around, there’s a good chance that homeowners won’t have to deal with these nodules, but if they’re a consistent problem, replastering the pool may be the only option.

Does water chemistry play a role?
While calcium nodules are a result of poor pool plastering and the regular wear and tear that comes with pool use, some pool owners may believe that water chemistry may cause nodules as well. However, research has shown that bond failure and ineffective plastering are the chief causes behind calcium nodules, and water chemistry has very little effect on their frequency. When a plaster pool is first filled with water, the plaster is hydrated by the pH-balanced water, and soluble calcium, or calcium hydroxide, is released into the water and will raise the pH level. Poolman professionals can assist homeowners through every step of this process to help maintain the overall water balance of the pool and remove any plaster dust that may remain after the job is completed.