100 Reasons why your Pool Water might be Cloudy

1. Inconsistent swimming pool chlorination. This is probably the #1 reason. If you don't keep enough chlorine in your pool ALL the time, you WILL have problems.
2. Dead algae is still in the swimming pool. If you had algae (the pool was green), but you killed it, and now the pool is cloudy blue or gray . . . dead algae may be the problem. Some types of dead algae are quite difficult to remove, especially with sand or cartridge filters.
3. Live algae is in the swimming pool. 95% of the time — or more — if your pool is green AND cloudy, it's algae. Kill it!
4. Swimming pool pump oversized for sand swimming pool filter (VERY common on aboveground pools) (More info)
5. Your pump not running long enough. (Adjust the timer!)
6. Calcium hypochlorite pool shock or chlorinating powder used incorrectly. (NOTE: Instructions on containers are incorrect!)
7. Adding sodium bicarbonate AND calcium chloride to the swimming pool at the same time. (Never, never do this!)
8. Too much sodium bicarbonate (pool alkalinity increaser).
9. Overdose of calcium chloride (pool calcium increaser).
10. Too much sodium carbonate (pool pH increaser).
    Your water shouldn't look like this!
11. Swimming pool pH level has drifted too high.
12. Swimming pool saturation index is too high. (This means pH Alk Cal Hardness are together too high.)
13. Swimming pool water has not been replaced in 5 years or more.
14. Iron or manganese in the pool fill water. (Cloudy PLUS colored!)
15. High calcium in swimming pool fill water. (From limestone springs, etc.)
16. Dissolved air in the pool fill water. (Usually, on a private water system)
17. Dissolved air in swim pool water due to tiny suction leak. (Piping leaks AHEAD of the pump can cause this.)
18. Bubbles in the water from swimming pool suction piping leak. (can make water look milky!)
19. Bubbles in the water from low pool water allowing pool skimmer to suck air.
20. Bubbles in the water because swimming pool pump drain plugs was improperly installed.
21. Bubbles in the water from leak at pool pump strainer lid.
22. Bubbles in water from suction side swimming pool chlorinator connection.
23. Too many people in the pool. (cloudy 24 hours later!)
24. Too much pee in the pool. (cloudy 24 hours later!)
25. Bather load is too high for the pool size.
26. Bather load is too high for the pump/filter.
27. PHMB (Baquacil, Softswim, et al.) has been used to treat the pool for 3 or more years without draining.
28. Added chlorine to PHMB (Baquacil, Softswim, et al.) pool.
29. Added copper algaecide to PHMB treated (Soft Swim) pool.
30. Added incompatible stain control agent to PHMB-treated (Baquacil) swimming pool.
31. “Topped off' PHMB treated swimming pool with fill water containing chlorine, copper or iron.
32. Pool filters all gummed up from long term (more than 1 season) use of PHMB (Baquacil) sanitizer.
33. Swimming pool filter all gummed up for other reasons.
34. Filter solidified with calcium or other minerals.
35. Broken internal pool filter piping.
36. DE filter not cleaned properly.
37. DE has built up and “bridged' grids in filter.
38. DE filter leaking DE into the pool.
39. “Bump' type DE filter is broken internally.
40. No DE in DE swimming pool  filter.
41. Cartridge swimming pool filter not cleaned.
42. Cartridge swimming pool filter cartridge ruined improper cleaning.
43. Cartridge swimming pool filter cartridge “pleats' have collapsed (common on Sta-Rite System 3 and other expensive “high capacity' filters)
44. Cartridge swimming pool filter has holes in it.
45. Cartridge swimming pool filter improperly installed, allowing water to bypass filter.
46. Cartridge swimming pool filter cartridge needs to be replaced
47. Multiport swimming pool valve on “Recirculate'.
48. Multiport swimming pool valve gasket damaged.
49. Multiport valve plumbed wrong.
50. Sand swimming pool filter has “channeled'.
51. Sand lost out of sand swimming pool filter. (Very common on above ground pools with sand filters.)
52. Sand swimming pool filter not backwashed completely.
53. Sand swimming pool filter backwashed using two speed pumps on low.
54. Coarse sandblast sand used instead of swimming pool filter sand. (Some dealers sell cheap and coarse sandblast sand as “filter sand'.)
55. Overdose of swimming pool clarifier.
56. Overdose of swimming pool stain/scale chemicals.
57. Overdose of alum (aluminum sulfate – old-fashioned swimming pool filter aid).
58. Use of alum or flocculant as swimming pool filter aid instead of flocculant.
59. Use of alum at improper swimming pool pH or alkalinity levels.
60. Overdose of other flocculant for swimming pool water.
61. Pool chlorine stabilizer WAY too high ( > 200 ppm). (Unless you compensate with corrected chlorine levels — see the “Best Guess Chart')
62. Swimming pool pump strainer basket all stopped up.
63. Pump impeller all stopped up with leaves, pine needles, goggle straps, etc.
64. Pool pump impeller worn down due to sand in lines.
65. Pump impeller worn down due to a piece of gravel or wire in volute.
66. Pump impeller not turning due to stripped threads on impeller.
67. Pool pump overheated, cracking case, and creating impeller bypass.
68. Pump not pumping due to air in lines.
69. Two speed pump left on low continuously.
70. Old brass (or iron) pool pump impeller is worn out.
71. Pool piping stopped up with chemicals.
72. Pool piping stopped up with golf ball.
73. Pool piping stopped up with billiard ball.
74. Swimming pool piping stopped up with plastic toy soldier, golf ball, etc.
75. Pool valves that should be opened, is closed.
76. Pool valves that should be closed, is open.
77. Gate valve stem broken, stopping proper flow
78. Ball valve stem broken, stopping proper water flow, or allowing improper flow.
    

    Properly filtered, circulated, and treated swimming pool water is beautiful!
79. Epoxy swimming pool paint chalking off (normally only at beginning of season).
80. Crummy non-epoxy, non-rubber base swimming pool paint (can chalk forever).
81. Poorly applied swimming pool paint chalking/flaking.
82. Newly plastered pool still releasing plaster dust.
83. Excessive tree pollen in pool.
84. Dust blown into pool.
85. Rainwater runoff (mud, goo) in swimming pool.
86. Oil/lotion spilled or carried into the pool by swimmers.
87. Pine sap or other tree sap in pool.
88. Pool vandalized with soap, detergent, motor oil, etc.
89. Use of “chlorine-free' chemicals, such as Chlor-Free.
90. Use of copper ionizers or liquids, without sufficient shocking.
91. Use of “minerals' or “catalysts', without sufficient shocking (oxidation).
92. Repeated use of “foamy algaecides' to “prevent' pool algae.
93. Repeated use of tile line, or pool water line, cleaning products.
94. Use of “phosphate removing' pool algae products (ALWAYS causes cloudiness; will eventually clear!)
95. Use of “phosphate remover' with marginal sand swimming pool filter. (may NOT clear up!)
96. Brushing an epoxy painted pool (see #64 and #65 above). (common at start of season)
97. Brushing an acrylic painted pool (see #64 and #65 above). (any time)
98. Plaster dust from recently applied swimming pool plaster. (normal)
99. Plaster dust from recently acid washed pool (not good!)
100. Brushing a freshly plastered pool (this is normal, and will quit after the plaster cures)

. . . and 6 Common Errors about Cloudy Swimming Pool Water!

1. Rain doesn't make pools cloudy! Usually the problem is that pool owners don't care for their pools during a rainy spell.
2. Too much chlorine makes pools CLEAR, if uncomfortable to swim in! Except for calcium hypochlorite, none of the pool chlorine materials can cause cloudiness, unless something else is in the pool, that shouldn't be.
3. Low calcium doesn't make swimming pools cloudy . . . EVER!
4. Low alkalinity doesn't make pools cloudy . . . EVER!
5. Low stabilizer doesn't make pools cloudy (but it can lead to low chlorine). However, in an outdoor pool this can result in low chlorine, which results in cloudiness.
6. Lack of clarifier doesn't make pools cloudy. A properly filtered, circulated and treated swimming pool will not be cloudy, even if without any clarifier.