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How To Eliminate Algae In A Pool

This article gives a complete list of steps to eliminate algae and try to prevent its return.  If doing a quick algae elimination make sure water parameters are correct and do steps 1 through 4.

Items Needed To Eliminate Algae In A Pool:

1)  Begin lowering the pH to 6.6 - 7.0.  (Aim for 6.6)

2)  Apply 1 quart non-metal algaecide during daylight hours.  If possible, apply the algaecide in the morning which is when algae feeds.

3)  Wait 12 hours.  Then put in non-chlorine shock (potassium monopersulfate), using the formula 5 lbs per 20,000 gallons of pool water. (double this amount to allow for a poosible second dose). 

4)  Wait 24 hours.  If the pool isn't 90% clear, add another dose of the non-chlorine shock.

Confirm all water parameters:

pH - 6.6 - 7.0

Copper- .4 ppm - .7 ppm

Calcium - 400+ppm (minimum 300 ppm)

Phosphates - 0 (maximum 200 ppm)

*If you have recurrent algae, follow the rest of these steps to eliminate the most common causes..


Filter Cleaning

Sand Filter With Sand or Glass:

1)  Take the top off of the filter and examine it.  Take out debris and check for dips in the media that might indicate a broken lateral.

       a)  If the filter is a sand filter with sand, pour a couple gallons of liquid acid in the filter covering the media.

       b)  If the filter is a sand filter with GlassPack Filter Media, pour in 2 gallons of regular household bleach, covering the media.

2)  Let the filter sit overnight and then backwash to waste.

DE Filter:   

1)  The filter should be broken down, the grids removed and soaked in a 2 parts water to 1 part liquid acid solution for 12 hours.  

2)  Reassemble the grids 

3) Add DE powder.

Testing Circulation

While the pump and filter are running, place a beach ball (or something that floats) on the surface of the water and watch how it moves.  If it gets stalled someplace that means the pool water isn't circulating effectively.

Make sure all return jets are pointing straight to the middle of the pool, not up, down or sideways.

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