Assuming the CYA test is accurate (which we really can't assume) . . . 5 ppm FC @ 40 ppm CYA is effective against some, but not all forms of green algae.
If you get a gallon of distilled water at Walmart, you can use a test sample composted of 1/4 cup pool water and 3/4 cup distilled. Mix, test, and multiply result x4.
Then dose to 15 - 20 ppm FC. Five gallons of 8% bleach added late in the day should do it . . . IF YOUR POOL WERE 30K gallons.
But, that's very unlikely. On rectangular liner pools WITH a deep end, typical dimensions and volumes are:
16 x 32 => ~20,000 gallons
18 x 36 => ~24,000 gallons
20 x 40 => ~30,000 gallons
So, unless your have an atypical liner pool, your volume is more likely to be 25,000 gallons, than 30,000 gallons. If so, 4 gallons of plain bleach would be a more appropriate dose.
Good luck!
Bookmarks