I have a customer with a pool FULL of algae.
Here are the specifics:
CH 500+ (tested twice)
6 year old plaster over gunite pool, 25,000 gallons
Because of the high CH number, I decided to try the bleach method of shocking the pool instead of Cal-Hypo. According to the pool calculator, I should add 518 ounces of 6% bleach. So I added 3 x 174 oz bottles of Walmart Ultra Bleach (6%) to the skimmer. This amount comes out to 522 oz. Close enough I thought. I also decided to add 10 ppm CYA to help the chlorine stay in the pool. For the next 3 1/2 hours I scrubbed all the steps, swimouts, spa, pool walls, pool floor etc. I also spent a lot of time fishing around the bottom for unseen organic debris. To give you an idea of water clarity, my pool brush disappears 12 inches under the surface. The filter pump ran the entire time.
At the end of the 3 1/2 hours, my TC was 0.5 ppm, not 10 ppm as anticipated. I tested this twice. Is this because my initial dosage was eaten up by the algae? Please tell me this is so
Before I left the house for the evening, I went to a nearby grocery store and bought 3 more bottles of Safeway regular bleach (6%) and added them to the skimmer. This came out to 546 oz, or a total of 1064 for the day.
Thanks for your replies. I'm kinda freaking out at this point! I can hear the Cal-Hypo calling to me from the garage!