Every pool owner runs into problems eventually. That’s just part of owning one. The water turns green. The pump starts making a noise it never made before. The filter stops keeping up. Someone gets out with red eyes and starts asking questions. None of it is fun, but most of it is fixable — and most of it is far less complicated than it looks once you understand what’s actually happening.
The pool owners who spend the least time dealing with problems are usually the ones who catch things early and understand what the warning signs mean. A green pool that gets addressed on day two is a few hours of work. The same green pool on day ten is a much bigger situation.
Here’s a rundown of the most common pool problems, what causes them, and how to fix them.
Water that’s turned green or gone cloudy is one of the first things pool owners notice and one of the most common complaints overall. The two problems look similar but have different causes and need slightly different approaches.
Green water almost always means algae. Green algae is the most common type, but mustard algae — which looks yellowish and tends to cling to pool walls — and black algae — which appears as dark spots and is the hardest to kill — can also take hold when conditions are right. All of them thrive when chlorine levels drop below effective range, when circulation is poor, or when the pH is out of balance and the chlorine present isn’t working efficiently.
To fix it, start by testing your water to understand the full chemical picture before adding anything. Brush all pool surfaces — walls, floor, and steps — to break algae loose from where it’s attached. Shock the pool with a high dose of chlorine — roughly one pound of shock per 10,000 gallons is a standard starting point for a moderate algae problem. Run the filter continuously until the water clears. Vacuum up the dead algae from the floor. An algaecide application after shocking helps prevent regrowth. Test and rebalance chemistry before anyone swims.
Black algae is the exception. It has a protective outer layer that makes it resistant to standard shock treatment. Scrubbing with a stiff brush to break that layer before applying a targeted algaecide is necessary. It often takes multiple treatment cycles to clear.
Cloudy water without a green color usually points to one of three things — a chemical imbalance, a filter issue, or environmental contamination. Start with the filter. A clogged or dirty filter can’t remove the fine particles that make water look hazy, and it’s the easiest fix. Check, clean, or backwash depending on your filter type.
If the filter is fine, test the water chemistry. pH outside the 7.2 to 7.6 range, low chlorine, high calcium hardness, or elevated cyanuric acid can all cause cloudiness. Adjust whatever is out of range. If chemistry and filtration both check out, you’re likely dealing with fine environmental particles — sunscreen residue, pollen, body oils — that are too small for the filter to catch efficiently. A pool clarifier binds these particles together into larger clumps the filter can remove. A flocculant works faster but requires vacuuming to waste afterward.
Pool water chemistry sounds complicated but really comes down to keeping a handful of numbers in range. When those numbers drift, everything else tends to follow — water clarity, equipment wear, and the experience of anyone swimming in the pool.
The recommended pH range for a swimming pool is 7.2 to 7.6. Water below 7.2 is acidic — it corrodes metal fittings, etches plaster surfaces over time, and irritates the eyes and skin of swimmers. Water above 7.8 promotes scaling on surfaces and equipment, reduces the effectiveness of chlorine significantly, and can encourage algae and bacterial growth.
To raise pH, add sodium carbonate — sold as soda ash. To lower it, add muriatic acid or sodium bisulfate. Add chemicals slowly, let them circulate fully, and retest before adding more. Making large adjustments all at once swings chemistry past the target and creates more work.
Low chlorine is the primary trigger for algae and bacterial growth. Keep free chlorine between 1 and 3 parts per million. Anything below 1 ppm and the sanitization is compromised. Shock the pool weekly during swim season to burn off combined chlorine — chloramines — which are the byproduct of chlorine reacting with contaminants and are what cause the sharp chlorine smell and eye irritation that people often blame on too much chlorine. That smell is actually a sign that more chlorine is needed, not less.
High chlorine — above 5 ppm — causes its own problems. Skin and eye irritation, bleached swimwear, and degraded pool equipment. If chlorine is too high, the simplest fix is to stop adding it and let sunlight and time burn it off naturally. Diluting with fresh water helps. A chlorine neutralizer can speed up the process if the pool is needed quickly.
Cyanuric acid — also called stabilizer or conditioner — protects chlorine from UV breakdown but causes chlorine lock at high concentrations. When cyanuric acid exceeds 80 to 100 ppm, chlorine becomes significantly less effective regardless of the level present. The only fix for excessively high cyanuric acid is dilution — partially draining the pool and refilling with fresh water.
Red eyes, itchy skin, and that distinctive chlorine smell coming off the water after swimming are usually caused by chloramines rather than excess chlorine. Chloramines form when chlorine combines with nitrogen compounds — sweat, urine, body oils — from swimmers. The fix is to shock the pool, which breaks down chloramines and restores free chlorine effectiveness. Encouraging swimmers to shower before entering the pool reduces the volume of contaminants that form chloramines in the first place.
The filter is the backbone of a clean pool. When it stops working properly, water quality deteriorates fast regardless of how well the chemistry is managed.
All filters need regular cleaning. Sand filters and DE filters require backwashing — reversing water flow to flush accumulated debris out through the waste line. Cartridge filters need to be removed and physically rinsed clean, and replaced periodically when they no longer clean effectively. A filter that’s working hard and clogged is a filter that’s doing its job — but it needs maintenance to keep doing it.
Signs of a filter that needs attention include cloudy water despite balanced chemistry, reduced return flow from the jets, or a pressure gauge reading significantly higher than normal. High pressure means the filter is full and restricted. Low pressure can mean a blockage on the suction side or a problem with the pump.
If the filter is clean and running but the water still won’t clear, check run time. Most residential pools need the filter running eight to twelve hours per day to maintain water quality. Running it four hours in high summer is often not enough. Also check that return jets are directed to create circulation across the full pool — dead spots with little water movement are where algae establishes first and where contaminants accumulate.
If you’re finding sand on the pool floor after the filter runs, the laterals inside the sand filter — the branched tubes at the bottom that hold the sand back — are cracked or broken. This requires opening the filter tank and replacing the damaged laterals. It’s not a complicated repair but does require draining and disassembling the filter.
Without a functioning pump, there’s no circulation, no filtration, and no chemical distribution. Pump problems are worth addressing quickly before the water quality follows.
A humming sound with no water movement usually means the motor is seized or has a failed capacitor. A grinding or screeching noise points to worn bearings inside the motor. A rattling or cavitation sound — like gravel moving through the pump — typically means there’s air getting into the suction line or the water level has dropped below the skimmer intake. Air in the suction line causes the pump to lose prime and move air instead of water, which damages the pump rapidly if left unaddressed.
Check the pump basket for blockages. Check that all valves on the suction side are fully open. Check that the water level is at the midpoint of the skimmer opening. If air is entering the system, inspect union fittings, valve stems, and the pump lid o-ring — any of these can allow air infiltration while the pump is running under suction.
A pump that won’t prime — meaning it can’t pull water up from the pool — is usually dealing with an air leak on the suction side or a blocked impeller. The pump basket should be full of water before startup. If it empties quickly after the pump turns on, air is getting in somewhere. Inspect fittings and the pump lid o-ring, which hardens and cracks over time. A cracked or flattened o-ring is one of the most common causes of pump priming problems and costs very little to replace.
If the motor is running but there’s no water movement, the impeller — the spinning component that moves water — may be clogged with debris. Leaves, hair, and small debris that pass through the pump basket can jam the impeller. The pump needs to be disassembled to clear it. This is a straightforward repair for someone comfortable with basic pool equipment maintenance, or a quick service call for a professional.
Not all water loss is a leak. Pools in warm weather lose water to evaporation — typically around a quarter inch per day in summer heat, and more on windy days or with a pool heater running. The bucket test is the standard way to distinguish evaporation from an actual leak. Fill a bucket with pool water and set it on a pool step so it’s at the same water temperature. Mark both the bucket water level and the pool water level. After 24 hours, compare the two. If the pool dropped more than the bucket, you have a leak somewhere.
Common leak locations include around fittings — skimmers, return jets, lights, and main drains — at the pump and filter equipment, and through cracks in the shell. Dye testing is the most reliable DIY method for locating a leak in the pool itself. Use a syringe with leak detection dye near suspected areas. If the dye gets pulled into a crack or fitting rather than dispersing, you’ve found the source.
Equipment leaks at the pump, filter, or heater are usually visible as wet ground or water stains around the equipment pad. Check all unions, valve stems, and pressure gauges for signs of seeping. O-rings, gaskets, and union threads are common failure points that are straightforward to replace once identified.
Shell leaks — cracks that penetrate the pool structure — need professional evaluation and repair. A pool losing significant water daily through a structural crack requires proper diagnosis before patching, since the underlying cause of the crack determines whether a surface repair will hold.
Stains on pool surfaces fall into two categories and the treatment for each is different — using the wrong approach can make the staining worse.
Brown or greenish staining from leaves, algae, berries, insects, or other organic material responds well to chlorine. Brushing the stain and then shocking the pool, or applying chlorine directly to the stain on a drained surface, breaks down the organic compounds. For stubborn organic stains, allowing granular shock to sit on the stain before brushing can be effective.
Reddish-brown rust stains from iron or blue-green staining from copper don’t respond to chlorine — in fact, adding chlorine to a pool with high metal content can make metal staining worse by oxidizing the metals out of solution. Ascorbic acid — vitamin C — is effective for iron and rust staining. Citric acid works well on copper staining. Metal stain removers formulated for pools are available and more straightforward than mixing your own solution. After removing metal stains, a metal sequestrant added to the water prevents the metals from redepositing. The source of the metals — whether it’s the water supply, corroding fittings, or algaecide overuse — should be identified and addressed to prevent recurrence.
Beyond the obvious issue of losing water, a pool that drops below the skimmer opening causes the pump to pull air rather than water, which can run the pump dry and damage it quickly. Keep the water level at the midpoint of the skimmer opening at all times. If the level is consistently dropping faster than evaporation accounts for, work through the leak diagnosis process above before just refilling repeatedly.
Foam sitting on the water surface is a sign of organic contamination — typically from body oils, sunscreen, shampoo, hair products, or soaps introduced by swimmers. High total dissolved solids over time can also cause foaming. Shocking the pool breaks down the organic compounds that cause foam. Anti-foam products treat the symptom quickly but don’t address the cause. The practical prevention is having swimmers shower before entering the pool, which dramatically reduces the volume of products that end up in the water.
Most pool problems that seem to appear suddenly have actually been developing over time. Pump bearings wear gradually. Filter media exhausts. O-rings harden and crack. Heater heat exchangers scale up internally. The pool owner who does annual equipment checks before the season opens tends to catch these things at the inconvenient stage rather than the emergency stage.
Pump motors typically last eight to twelve years with good maintenance. Sand filter media should be replaced every five to seven years as the sharp edges that do the filtering gradually smooth and lose effectiveness. Cartridge filter elements need replacement every one to three years depending on use. Heaters are variable depending on water chemistry — pools with consistently unbalanced water corrode heat exchangers faster than well-maintained pools.
When equipment is old enough that it’s failing regularly, the conversation shifts from repair to replacement. Repeated repairs on aging equipment often cost more over two or three seasons than a replacement would have cost upfront.
Most water chemistry and minor equipment issues are manageable by pool owners who understand what they’re dealing with. But some situations are genuinely better handled by a professional.
Structural cracks — cracks in the pool shell that are causing water loss — need professional evaluation before repair. Patching a structural crack without understanding what caused it leads to the same crack reappearing. Electrical issues around pool lights, heaters, or pump wiring are not DIY territory — water and electricity in combination carry real risk and require a qualified technician. Major equipment failures — a seized pump motor, a cracked filter tank, a failed heater — are most efficiently handled by someone with the tools, parts access, and experience to diagnose and repair quickly.
If something’s been tried multiple times and the problem keeps coming back, that’s usually a sign the diagnosis is wrong rather than the repair. Getting a professional opinion on a recurring problem often costs less in the long run than continued trial and error.
If your pool is giving you trouble and you’d rather have someone who does this every day take a look, that’s what we’re here for. At Spas and More, we handle pool repair, spa services, and everything in between. Give us a call and we’ll figure out what’s going on.
(423) 337-1859
spasandmore.net
timspasandmore@gmail.com
Monday through Friday, 8:00 AM to 8:00 PM.
