Iím considering switching from the trichlor hockey pucks to liquid chlorine. I wanted to get a feel for how much bleach or pool store liquid chlorine Iíd need. So I did a chlorine usage calculation for the trichlor pucks. I purchased the pucks on Aug. 5, 2010. I assumed I started using those pucks two weeks after I bought them. I also know when Iíve opened and closed the pool since then. It turns out that Iíve used 35 pounds of pucks across a span of 30 weeks. That works out to be just 2.67 ozs/day for a 22,500 gallon pool in Massachusetts that gets full sun from about 8:00 AM until sunset. When I stop to think about it that doesnít sound like much chlorine. :P We do have a mineral sanitizer cartridge as part of our pool equipment so I run lower chlorine levels. And as I recall last summer I needed to shock the pool two or three times because of cloudiness/beginning algae. So this year Iíve been running a higher chlorine level (1.5 ppm or so). The pucks weigh 8 ounces each so Iíve been using just one third of a puck per day. The bather load is light and does not include dogs or kids.
Using the Pool Calculator on this forum I calculate that 2.67 ozs of trichlor is equivalent to 43 ounces of 5.25% bleach or 18 ounces of 12.5% liquid chlorine. So Iíd be looking at adding a quart and third of bleach per day, or a little over a pint of the liquid pool shock. Does this seem reasonable? I realize these are average values. I plan to dose more when we have very sunny days and dose less when itís cloudy.