Why Is My Pool Chalky? Causes and Solutions
Have you noticed your pool looking a bit cloudy or “chalky” lately? Maybe there’s a fine white dust that settles on the floor or makes the water look dull and milky. You’re not imagining things — and you’re not alone. A chalky pool is a common issue, but the good news is it’s usually fixable once you know what’s causing it.
Let’s dive into what might be going on and how to get your pool back to sparkling blue.
💨 1. High Calcium Levels (Scaling)
If your pool feels rough to the touch or you see white residue on tiles or around the waterline, calcium scaling is often to blame.
When calcium hardness levels get too high, the minerals start to precipitate out of the water, leaving behind a white, chalky coating or dust.
What causes it:
Using hard water to top up the pool
Too much calcium-based chlorine (like cal-hypo)
High pH or alkalinity levels
The fix:
Test your water for calcium hardness — it should be between 200–400 ppm
If it’s high, partially drain and refill the pool with fresh water
Balance your pH (7.2–7.6) and total alkalinity (80–120 ppm)
Avoid calcium-based sanitizers if your levels are already high
🧪 2. High pH or Alkalinity
Even if your calcium levels are fine, high pH or total alkalinity can still make the water cloudy or chalky.
What happens:
When the pH or alkalinity rises too high, calcium can fall out of solution, making the water look dull and leaving that chalky feel.
The fix:
Test your pool water regularly
Add pH reducer (acid) in small doses to bring your levels back in range
Keep pH between 7.2–7.6 and total alkalinity around 100 ppm
🧴 3. Chemical Imbalance or Overdosing
Sometimes the chalkiness comes from adding too many chemicals at once or not allowing them to circulate properly.
Common culprits:
Too much chlorine shock
Mixing incompatible chemicals
Adding chemicals without brushing or running the pump
The fix:
Only add one chemical at a time
Always run the pump while chemicals circulate
Brush the pool after adding granular products to prevent residue buildup
🌫️ 4. Filter or Circulation Problems
If your filter isn’t doing its job, that fine white dust won’t get removed — it’ll just keep swirling around.
What to check:
Clean or backwash your filter
Check for cracks or worn filter media
Make sure the pump is running long enough each day (usually 8–10 hours in summer)
The fix:
Give the filter a thorough clean
Consider a clarifier to help the filter grab smaller particles
If the water is still hazy after a few days, it might be time for a filter media replacement
💧 5. Plaster or Surface Breakdown
In older or poorly balanced pools, the interior surface can start to break down, releasing a chalky residue into the water.
Signs to look for:
Rough, powdery spots on the walls or floor
Consistent white dust even after cleaning
The fix:
Keep your water balanced to protect the surface
If damage is already visible, you may need a professional inspection to determine if resurfacing is needed
🧼 How to Prevent a Chalky Pool
Test your water weekly
Maintain proper pH, alkalinity, and calcium hardness
Run your filter daily and clean it regularly
Use quality chemicals and add them correctly
Schedule a professional service every few months to keep your system in top shape
🏊♂️ Need Help Getting Your Pool Back to Crystal Clear?
If your pool’s turned chalky and you’re not sure why, don’t stress — we can help!
Our team at Mick’s Pool Care can test your water, diagnose the problem, and get your pool sparkling again in no time.
📞 Contact us today to book a service or water test.