Pool
Chemistry:   Cloudy Water Problems

Cloudy Water Problems

There are few more frustrating problems than cloudy water.  Not only is it frustrating, but
it also is dangerous because it keeps you from being able to see swimmers who may be in trouble.  If the water is cloudy, you should not swim or allow anyone else
to swim in the pool until the water is cleared up.

Turbidity (cloudiness) in the water is caused by undissolved particles
in the water.  There are basically two factors that can lead to cloudy water, water chemistry and filtration.  The problem can be cause by one or
the other or both.

The first thing to consider is water chemistry, then filtration.

Water Chemistry

When reviewing the water chemistry on a pool, it is important to look at all possible chemical
causes.

Low Chlorine – a low chlorine level will cause materials in the
water to be un-oxidized.  It will also allow algae to grow in the water, leaving a green tint.

High pH – a high pH level will cause cloudiness because of carbonate
materials in suspension that are not able to be dissolved into solution. The pH should be around 7.4-7.6.  If it is allowed to creep up and over 8.0, the water
becomes more prone to cloudiness.

High Total Alkalinity – a high total alkalinity level will cause cloudiness because of
carbonate materials in suspension that are not able to be dissolved into solution. As the Total Alkalinity approaches 130, the water becomes very saturated and much more
prone to cloudiness after routine additions of chlorine shock or soda ash. 

NOTE:  A high Total Alkalinity is more likely to cause cloudiness than a high pH is. 

(See Solution vs. Suspension under Total
Alkalinity Intro.)  

High Calcium Hardness – a high calcium hardness can
be a contributing factor, but is generally not the root cause of water cloudiness.

Filtration (and Circulation)

If the water chemistry on a pool has been maintained at proper levels consistently and the pool
is still cloudy, then it is important to look at equipment issues to be certain that the water is circulating and filtering properly.