Why is my pool green?

Green pools.  Is there anything more annoying than waking in the morning and looking out the window to find the pool green?  Ugh!

Here’s the thing, a green pool is typically caused by an algae outbreak in the water.  Algae thrives in water that is not properly sanitized or circulated.  Let’s look at some possibilities as to why the pool may have turned green.

Lack of Chlorine / Bromine sanitizer.  Your sanitizer level needs to be kept in proper range at all times in order to prevent the growth of algae.  Chlorine is ideal between 1-3 ppm, while Bromine is ideal at 2-4 ppm. 

Insufficient Circulation.  Algae blooms in stagnant water, and quickly if the stagnant water is warm.  Ensure the circulation system is running properly, this may be as easy as performing a backwash on the filter, or could indicate issues elsewhere in the circulation system.  Start by ensuring the flow of water is not being impeded by a dirty filter.

Inadequate maintenance to the pool.  The pool requires vacuuming of the floor and brushing or vacuuming to the walls to remove any bacteria or algae that may be clinging to them.  When algae is clinging to a surface, your sanitizer cannot destroy it, it needs to be free floating in the water.  So brushing and vacuuming the pool is vital to remove the algae spores.  Tip:  Remember to brush in the dead spots of the circulation system – under the return jets and beside stairs/ladders.  These areas are impeding the flow of the water and need extra care to ensure the water is not sitting stagnant.

To resolve the issue: Test the pool water for any imbalances, brush the pool walls and floor, shock/oxidize the pool water, use a heavy hitting algaecide and follow it up with a clarifying agent.  (Once algae is destroyed it will turn from green to a grey particulate matter, you will want the clarifier to clear the particulate matter and keep the pool from appearing cloudy.

**Once you have fixed the algae bloom you should clean any equipment you used in the pool during the time of repairing the issue as algae may have adhered to these pieces of equipment.  You can re-introduce the algae to the water each time you use the equipment after the bloom.

To prevent future outbreaks, test your sanitizer levels frequently to ensure you are within the ideal range. Shock/Oxidize the pool on a weekly basis and pair it with a preventative algaecide.