Cloudy Swimming Pool Water

100 Reasons for Cloudy Swimming Pool Water!

I keep getting emails like this:
"My swimming pool is cloudy. Tell me why. Please hurry; I need an answer now!".

When I'm not too tired, not too far behind, and in a good mood -- a very rare combination, in summer -- I answer politely.

When I'm tired and in a bad mood, I tend to dash off sarcastic and pointed emails. Usually, the note includes some smart a## remark to the effect that I only answer questions "NOW" from customers who are paying me, and not from folks who waltz in to my website and 5 minutes later dash off an email demanding my immediate response.

Thank God for the "DRAFT" bucket: I almost always delete these emails 30 minutes later. Still, I've wasted 5 - 10 minutes on an email nobody will read, gotten myself worked up, and not anwered.

So I wrote this page.

If you recognize something about your pool, there are some links at the bottom that may help. Or, you can try the forum: www.PoolForum.com. And, you can subscribe, which opens the doors to over 200 more pages of information, plus I try to answer subscriber questions individually.

100 Reasons for Cloudy Swimming Pool Water!

Inconsistent chlorination (or other sanitizer/shock).
This is probably the #1 reason.
Dead algae is still in the 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.
Live algae is in the pool.
95% of the time -- or more -- if your pool is green AND cloudy, it's algae. Kill it!
Pump oversized for sand filter (very common on aboveground pools)
Pump not running long enough.
Calcium hypochlorite shock or chlorinator
Adding sodium bicarbonate AND calcium chloride at the same time.
Too much sodium bicarbonate (alkalinity increaser).
Overdose of calcium chloride (calcium increaser).
Too much sodium carbonate (pH increaser).
pH has drifted too high.
Saturation index is too high.
Pool water has not been replaced in 5 years or more.
Iron or manganese in the fill water.
High calcium in fill water.
Dissolved air in the fill water.
Dissolved air in pool water due to tiny suction leak.
Bubbles in the water from suction piping leak. (can make water look milky!)
Bubbles in the water from low pool water allowing skimmer to suck air.
Bubbles in the water because pump drain plugs was improperly installed.
Bubbles in the water from leak at pump strainer lid.
Bubbles in water from suction side chlorinator connection.
Too many people in the pool. (cloudy 24 hours later!)
Too much pee in the pool. (cloudy 24 hours later!)
Bather load is too high for the pool size.
Bather load is too high for the pump/filter.
PHMB (Baquacil, Softswim, et. al.) has been used to treat the pool for 3 or more years without draining.
Added chlorine to PHMB (Baquacil, Softswim, et. al.) pool.
Added copper algaecide to PHMB pool.
Added incompatible stain control agent to PHMB pool.
'Topped off' PHMB pool with fill water containing chlorine, copper or iron.
Filter all gummed up because of PHMB use.
Filter all gummed up for other reasons.
Filter solidified with calcium or other minerals.
Broken internal filter piping.
DE filter not cleaned properly.
DE has built up and 'bridged' grids in filter.
DE filter leaking DE into the pool.
'Bump' type DE filter is broken internally.
No DE in DE filter.
Cartridge filter not cleaned.
Cartridge filter cartridge ruined improper cleaning.
Cartridge filter cartridge 'pleats' have collapsed (common on System 3 and other large filters)
Cartridge filter has holes in it.
Cartridge filter improperly installed, allowing water to bypass filter.
Cartridge filter cartridge needs to be replaced
Multiport valve on "Recirculate".
Multiport valve gasket damaged.
Multiport valve plumbed wrong.
Sand filter has 'channeled'.
Sand lost out of sand filter.
Sand filter not backwashed completely.
Sand filter backwashed using two speed pump on low.
Coarse sandblast sand used instead of filter sand.
Overdose of clarifier.
Overdose of stain/scale chemicals.
Overdose of alum (aluminum sulfate).
Use of alum or flocculant as filter aid instead of flocculant.
Use of alum at improper pH or alkalinity levels.
Overdose of other flocculant
Stabilizer WAY too high ( > 200 ppm).
Pump strainer basket all stopped up.
Pump impeller all stopped up.
Pump impeller worn down due to sand in lines.
Pump impeller worn down due to a piece of gravel or wire in volute.
Pump impeller not turning due to stripped threads on impeller.
Pump overheated, cracking case, and creating impeller bypass.
Pump not pumping due to air in lines.
Two speed pump left on low continuously.
Old brass (or iron) pump impeller is worn out.
Piping stopped up with chemicals.
Piping stopped up with golf ball.
Piping stopped up with billiard ball.
Piping stopped up with plastic toy soldier.
Valve that should be opened, is closed.
Valve that should be closed, is open.
Gate valve stem broken, stopping proper flow
Ball valve stem broken, stopping proper flow, or allowing improper flow.
Epoxy paint chalking off (normally only at beginning of season).
Crummy non-epoxy, non-rubber base paint (can chalk forever).
Poorly applied paint chalking/flaking.
Newly plastered pool still releasing plaster dust.
Excessive tree pollen in pool.
Dust blown into pool.
Rainwater runoff (mud, goo) got in pool.
Oil/lotion spilled in pool.
Pine sap or other tree sap in pool.
Pool vandalized with soap, detergent, motor oil, etc.
Use of 'chlorine-free' chemicals, such as Chlor-Free.
Use of copper ionizers or liquids, without sufficient shocking.
Use of 'minerals' or 'catalysts', without sufficient shocking (oxidation).
Repeated use of "foamy algaecides"
Repeated use of tile line, or water line, cleaning products.
Use of "phosphate removing" anti-algae products (ALWAYS causes cloudiness; will eventually clear!)
Use of "phosphate remover" with marginal sand filter. (may NOT clear up!)
Brushing a epoxy painted pool (see #64 and #65 above). (common at start of season)
Brushing a acrylic painted pool (see #64 and #65 above). (any time)
Plaster dust from recently applied plaster. (normal)
Plaster dust from recently acid washed pool (not good!)
Brushing a freshly plastered pool (this is normal, and will quit after the plaster cures)

And, 6 Common Errors about Cloudy Swimming Pool Water!

Rain doesn't make pools cloudy!
Usually the problem is that pool owners don't care for their pools during a rainy spell.
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.
Low calcium doesn't make pools cloudy . . . EVER!
Low alkalinity doesn't make pools cloudy . . . EVER!
Low stabilizer doesn't make pools cloudy (but it can led to low chlorine).
However, on an outdoor pool this can result in low chlorine, which results in cloudiness.
Lack of clarifier doesn't make pools cloudy.
A properly equipped and treated pool will not be cloudy, even if clarifier is not used.

Links that might help . . .

Swimming Pool Chemistry and the "Gotcha's"
These two pages cover a number of problems briefly.
Swimming Pool Test Tips: OTO & DPD ABC's!
Basic testing: if you can't test, you can't maintain your pool!
Guide to Avoiding Algae
A general guide to PREVENTING algae.