We have a 14000 gallon pool, somewhat smaller than yours. We did the conversion from start to swimming in 3 days (Friday night to Monday afternoon in the pool) HOWEVER, we monitored the clorox ppm every 1 1/2 to 2 hours and continued to add clorox to keep it at 15ppm till it held 15ppm overnight and the combined clorine was 0). Our water also had no green color but was a hazy white cloudy mess. By monday night, it was clear and we were swimming. By Tuesday afternoon we were amazed at how much clearer still it had become. That was one week ago, we have crystal (and I cannot emphasize that enough... CRYSTAL!!!) clear water now. The 15ppm would not hurt you to swim in from what I have read. At the time we first got in to swim the reading was down to about 7ppm. Backwash your filter often (we did it 6 or 8 times a day) to keep the filter clear and to avoid the pressure building. That helped a lot. We also used the brush to brush down the sides to brush off the top layer of what we believe was white mold and expose the lower layers of mold to be killed by the clorox, that helped as well.

Good Luck, you will be SO HAPPY that you have decided to do this.