White Flakes in Your Pool: What Causes Them and How to Get Rid of Them
Are you finding white flakes floating in your swimming pool, collecting on the floor, or blowing out of the return jets? In many cases—especially in saltwater pools—the flakes are calcium carbonate scale that has formed inside the pool equipment or salt chlorine generator.
Quick Answer: What Are the White Flakes?
If you have a saltwater pool and the flakes are white, brittle, and appear to be coming from the return jets, the most likely cause is calcium scale breaking loose from the salt chlorine generator cell.
The flakes can be vacuumed out, but if the pool water remains scale-forming, they will usually come back. The long-term solution is to test and properly balance the pool water and inspect the salt cell for calcium buildup.
Start Here: Bring Us a Water Sample
Before adding chemicals or making major adjustments, we highly recommend bringing a fresh pool-water sample to Premier Pool & Spa.
White calcium flakes are usually a symptom of the pool's overall water balance. pH, total alkalinity, calcium hardness, water temperature, and other factors all work together. Looking at just one number can lead to the wrong correction.
Before coming in, text us pictures of the pool and equipment if possible. Pictures are especially helpful if they show:
- The white flakes or material
- The pool water and pool surface
- The entire equipment pad
- The filter
- The salt chlorine generator and control panel, if equipped
The Most Common Cause: Calcium From a Salt Chlorine Generator
If your pool has a salt chlorine generator, the salt cell is one of the first places to investigate.
A salt chlorine generator creates chlorine through electrolysis. As this process occurs, the conditions immediately around portions of the cell plates can become temporarily much more scale-forming than the rest of the swimming pool.
Calcium carbonate can then form on the cell plates. Eventually, some of that calcium can break loose, travel through the plumbing, and be discharged into the swimming pool through the return jets.
Signs the Salt Cell May Be the Source
- Your pool uses a salt chlorine generator.
- The flakes appear near or below the pool return jets.
- The material is white and brittle.
- The flakes crumble relatively easily.
- You can see white scale buildup inside the salt cell.
- The flakes return after the salt system has been operating.
If calcium is repeatedly forming inside the salt cell, cleaning the cell may temporarily correct the symptom, but it does not necessarily correct the reason the scale formed.
Why Does Calcium Form?
Calcium scale is more likely to form when the water becomes excessively scale-forming. This is determined by several water conditions working together rather than by calcium hardness alone.
High pH
Elevated pH is one of the biggest contributors to calcium carbonate scale. As pH increases, calcium becomes more likely to precipitate from the water and form solid deposits.
Total Alkalinity
Total alkalinity helps stabilize pH. Excessively high alkalinity—particularly when combined with elevated pH, calcium hardness, and water temperature—can contribute to scale formation.
Calcium Hardness
Calcium is naturally present in pool water. Higher calcium levels can increase the likelihood of scale, but calcium hardness should never be evaluated by itself.
Water Temperature
Warmer water becomes more prone to calcium carbonate scale. This is one reason calcium is commonly found inside heaters and salt chlorine generator cells.
What Should My Pool Chemistry Be?
There is no single chemistry adjustment that should automatically be made whenever white flakes are found. The entire water test should be reviewed before deciding what needs to be changed.
| Water Test | Premier Pool & Spa General Guidance | Why It Matters |
|---|---|---|
| pH | 7.2–7.8 Ideal range generally 7.4–7.6 |
High pH greatly increases the likelihood of calcium scale. |
| Total Alkalinity – Standard Pool | 125–150 ppm | Helps stabilize pH and maintain proper water balance. |
| Total Alkalinity – Salt / Chlorine Generator Pool | 80–150 ppm | Saltwater pools may operate properly at a lower alkalinity than traditionally chlorinated pools. |
| Calcium Hardness | Depends on pool surface and complete water balance | Calcium should be evaluated together with pH, alkalinity, temperature, and pool-surface type. |
How to Get White Calcium Flakes Out of the Pool
Once you have identified the material and started correcting the cause, the flakes already in the pool can normally be removed through regular cleaning and filtration.
Brush the Pool
Brush the walls, floor, steps, and other pool surfaces to loosen any material that has settled or attached itself to the pool.
Vacuum the Flakes
Vacuum settled flakes from the pool floor. If there is a very large amount of material, vacuuming to waste may sometimes be preferable so the material does not have to pass through the filtration system.
Clean or Backwash the Filter
If the filter has captured a significant amount of material, clean or backwash it as appropriate for your specific filtration system.
Inspect the Salt Cell
If the pool has a salt chlorine generator, inspect the cell for visible calcium deposits.
Follow the salt-system manufacturer's instructions for cleaning the cell if scale is present.
Correct the Water Balance
This is the most important part. If the pool remains scale-forming, calcium can simply form again after the existing deposits are removed.
What If the White Material Is Not Calcium?
Not every white substance found in a swimming pool is calcium. Where the material appears, how it feels, and what type of equipment you have can help identify the cause.
DE Powder Returning to the Pool
If you have a traditional diatomaceous earth (DE) filter, white or light-gray material coming from the return jets may be DE rather than calcium.
Damaged filter grids, a damaged manifold, an improperly assembled filter, or another internal filter problem can allow DE to travel through the filter and return to the swimming pool.
DE is normally more powder-like than the hard or brittle flakes commonly associated with calcium scale. It may collect on the pool floor beneath the return jets shortly after the filter begins operating.
Plaster Dust
Newly plastered or resurfaced swimming pools can produce fine white material as the new surface cures. This is generally more powder-like than the larger brittle flakes commonly associated with salt-cell calcium deposits.
Water chemistry is especially important while a new plaster surface cures. Follow the startup procedure provided by the pool builder or plaster contractor.
Scale Breaking Off Pool Surfaces or Equipment
Calcium scale can also form elsewhere in the swimming pool system, including:
- Tile and waterline surfaces
- Pool heaters
- Plumbing
- Salt chlorine generator cells
- Pool surfaces
- Other equipment exposed to scale-forming water
Pieces of these deposits can eventually break loose and appear in the pool. If the flakes continually return, identifying where they originate is important.
Why Are White Flakes So Common in Saltwater Pools?
A common misconception is that the salt itself is turning into white flakes. That generally is not what is happening.
A salt chlorine generator uses the chloride in dissolved salt to produce chlorine. During this electrochemical process, conditions immediately around portions of the cell plates can encourage calcium carbonate to precipitate from the water.
Calcium can accumulate on the plates and eventually break loose. The pool's circulation system then carries the flakes through the plumbing and out of the return jets.
This is why a saltwater pool may produce noticeable calcium flakes even when there is not obvious calcium scale throughout the rest of the pool.
The appropriate correction is usually proper water balance and salt-cell maintenance rather than eliminating the salt system.
Should I Use a Scale-Control Product?
Scale-control or sequestering products can be helpful in certain swimming pools, particularly when source water contains high mineral levels or when correcting calcium hardness through water replacement is impractical.
However, these products should not be used as a substitute for correcting improper water balance.
We recommend testing the water first so we can determine whether a scale-control product is appropriate for your specific pool.
What If the White Flakes Keep Coming Back?
If you clean the pool or salt cell and the flakes return shortly afterward, something is still allowing calcium to precipitate.
At that point, the following should be evaluated together:
- pH
- Total alkalinity
- Calcium hardness
- Water temperature
- Salt level
- Salt-cell condition
- Pool-surface type
- Source-water chemistry
- The pool's overall water saturation balance
Repeatedly cleaning the salt cell without correcting the reason calcium is forming treats the symptom rather than the cause.
Frequently Asked Questions
Are white flakes in a saltwater pool normal?
They are fairly common, but recurring flakes generally indicate calcium is building up somewhere in the system—often inside the salt cell. The pool's water balance should be checked rather than simply continuing to remove the flakes.
Are the white flakes actually salt?
Usually not. Pool salt remains dissolved in the water. White flakes coming from a saltwater pool are much more commonly calcium carbonate scale.
Why are white flakes coming out of my pool returns?
In a saltwater pool, one of the most common causes is calcium scale breaking loose from the salt chlorine generator cell and being carried through the return plumbing. In a pool with a DE filter, powder coming from the returns can also indicate an internal filter problem.
Does high calcium hardness always cause white flakes?
No. Calcium hardness is only one part of water balance. pH, total alkalinity, temperature, pool-surface type, and other factors affect whether calcium remains dissolved or forms scale.
Should I clean my salt cell if I see white flakes?
Inspect the cell first. If calcium buildup is visible, clean it according to the salt-system manufacturer's instructions. Avoid unnecessary or excessive acid cleaning because repeated acid exposure can shorten cell life.
Not Sure What the White Flakes Are?
Bring a fresh water sample to Premier Pool & Spa and we can test the water and help determine the most likely cause.
For the best assistance, text us pictures of the white material, pool, equipment pad, filter, and salt system before coming in. An accurate water test combined with pictures of the equipment gives us considerably more information than trying to diagnose the problem from the flakes alone.
Premier Pool & Spa
2985 Water Tower Place
Chanhassen, MN 55317
