Troubleshooting Common Pool Problems
Even with steady maintenance, pools throw the occasional problem at you: cloudy water, stubborn algae, a pump that won't prime. Most of them have a clear cause and a straightforward fix once you know what you are looking at. Find your symptom below, open it, and you'll see the likely causes alongside the fix.
Find Your Symptom
Cloudy or dull water
Likely causes
- Inadequate filtration or a dirty filter
- Imbalanced pH or low sanitizer levels
- Excess debris, pollen, or high bather load
How to fix it
- Check and clean the filter: if the pressure gauge is high, backwash or replace cartridges.
- Shock the pool: use a chlorine or non-chlorine shock to clear organic contaminants.
- Balance the water: adjust pH, alkalinity, and sanitizer to range.
Algae growth (green, mustard, or black)
Identify the type
- Green: most common, easy to treat.
- Mustard: yellowish, often clings to walls.
- Black: the most stubborn, needs aggressive treatment.
How to fix it
- Brush and vacuum: scrub walls and floors to expose algae to sanitizer.
- Shock and algaecide: use a shock treatment plus a targeted algaecide.
- Run the filter 24/7: until the algae is gone, then backwash or clean it. See the full algae treatment guide.
Foamy or sudsy water
Likely causes
- Overuse of algaecides or clarifiers
- Residues from lotions, soaps, or hair products
- Low calcium hardness
How to fix it
- Dilute: partially drain and refill if foam is severe.
- Balance chemistry: keep calcium hardness at 200–400 ppm.
- Limit chemical overuse: cut back on unnecessary algaecide and clarifier.
- Rinse before swimming: a quick shower reduces contaminants.
Chlorine smell or eye irritation
The real cause
- High chloramine levels — caused by insufficient free chlorine, not excess chlorine.
How to fix it
- Shock the pool: breaks down chloramines and restores free chlorine.
- Improve ventilation: for indoor pools, ensure good air circulation.
Myth: A strong “chlorine” smell usually means too little free chlorine, not too much - it’s the chloramines you’re smelling. The fix is to shock up, not back off.
Pump won't prime or weak water flow
- Pump not priming: check for air leaks in the suction line and make sure the water level is adequate.
- Reduced water flow: clean clogged skimmer and pump baskets, inspect for plumbing blockages.
- Clogged or dirty filter: backwash or clean cartridges to restore flow.
- Check O-rings: worn or damaged O-rings cause air leaks; replace if necessary.
If the pump still won't prime or filter pressure stays high, contact a pool service professional.
Stains on pool surfaces
Metal stains
- Brownish or rusty stains from iron or copper.
- Use metal sequestrants or ascorbic acid for spot removal.
Organic stains
- Green or brown stains from leaves, berries, or algae.
- Shock, brush, and maintain proper sanitizer levels.
Most of these problems come down to the same fix: figure out the real cause, keep the water tested and circulating, and deal with small issues before they grow. When something keeps coming back no matter what you try, call a pool professional to check for a mechanical or structural problem underneath it.
Frequently Asked Questions
Why is my pool water cloudy even though the chlorine is fine?
Cloudy water with normal chlorine is almost always a filtration or balance issue, not a sanitizer one. Check the filter pressure and backwash or clean it if it is high, then confirm pH and alkalinity are in range. Fine particles that slip through a tired filter clear up fastest with a clarifier and a full filter cycle.
Does a strong chlorine smell mean there is too much chlorine?
No - it usually means too little. That smell is chloramines, which form when free chlorine is too low to finish off contaminants. The fix is to shock the pool up to breakpoint, not to add less chlorine.
Why won't my pool pump prime?
A pump that won't prime is almost always pulling air instead of water. Check that the water level is above the skimmer mouth, the pump basket lid and O-ring seal tightly, and there are no cracks or loose fittings on the suction side. Fill the pump basket with water before restarting to help it catch.
When should I call a pool professional?
Call a pro when a problem keeps returning no matter what you try, when filter pressure stays high after cleaning, or when you suspect a leak or an equipment failure you can't diagnose. Recurring issues often point to a mechanical or structural cause underneath the symptom.