
What causes calcium in pools?
Calcium nodules in pools usually occur due to delamination, which is a gap between the plaster and the substrate. If the pool has a bonding issue, like an air pocket, it can lead to plaster cracking and allow calcium hydroxide to seep into the water. When this calcium interacts with the pool’s alkaline water, it produces calcium carbonate, forming nodules on the pool’s surface.
How to remove calcium nodules from pool plaster?

- Drop the pH slightly: Lowering your pool’s pH to around 7.0–7.2 makes the calcium softer and easier to remove. Just don’t forget to raise it again after!
- Scrub like a pro (but gently): Use a pumice stone, soft plastic scraper, or emery cloth. No metal tools, your plaster will thank you later.
- Repeat if needed: Some nodules are stubborn. You may need to scrub them a few times over a couple of months until they stop regrowing.
- Try a scale-softening agent: Products like SC-1000 can help loosen buildup, but they won’t fix deeper problems.
According to the National Plaster Council, 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 in calcium noodles?

Some folks might think that the water’s chemistry is the big deal when it comes to calcium nodules, but the real deal is that it’s more about the bonding and how the plaster was put on, not the water’s make turns out, the chemistry of water doesn’t really affect how often these nodules show up.
This interaction is crucial because it ensures that the plaster sets properly and forms a smooth, even surface. When you mix this stuff with water, it starts to dissolve and spits out something called calcium hydroxide, which is basically soluble calcium.
When you add this calcium stuff to the pool water, it can make the pH go up, and that’s something you got to think about for keeping the pool in good shape. Amenity Pool Services are here to help you keep your pool in top shape, walking you through every step of the maintenance process.
What is a calcium releaser?
A calcium releaser is a non‑acid, non‐toxic pool tile and plaster cleaner that mimics acid action to safely dissolve and lift calcium scale and mineral efflorescence, without harming surfaces or disrupting water chemistry.
It’s got this “acid-like” mix that softens up calcium buildup, making it easy to clean off.
- Prepare the area: Lower water level so scale is dry. Loosely chunks should be softened with plastic putty scraper.
- Apply generously: Lay down calcium releaser over the dried scale. Fizzing is to be observed. The fizz is an indication of cleaner working, so give it a few minutes to settle down.
- Light scrubbing: Employ a nylon pad or stiff brush to remove soft deposits. Repeat application if so desired.
- Rinse well: Flush every bit of residue with clean water until the water film disappears so as to keep the integrity of the pool’s chemistry.
Properly working calcium releaser, along with the maintenance of good water chemistry and inspection-level cleanliness, will transform your pool into an attraction backyard oasis. Keep it safe, smart, and sparkling!
FAQ’s
1. How calcium nodules appear in pool plaster?
Calcium nodules form when calcium hydroxide exudes from behind or below a pool plaster, usually through microscopic cracks or bonding failures such as delamination. This compound interacts with the pool water to solidify into calcium carbonate, which looks like little white bumps on the plaster surface.
2. Is water chemistry responsible for calcium nodules?
No, in fact. Unlike other calcium scale problems, calcium nodules are not the product of unbalanced water chemistry. They are due to destabilized plaster bonding, shrinkage cracks, or weaknesses in the structure.
3. Can calcium nodules impair a pool for extended periods?
Yes, particularly if they’re endemic or recurrent. With persistent nodules, we may be looking at deeper issues with the plaster or the pool’s structure, requiring a full repair procedure like replastering.
4. Can calcium nodules be prevented in pool?
Yes, mainly by good plaster work and bonding at construction time. According to experts like the National Plaster Council, a properly done plaster job is key to avoiding nodules.