Oh, okay. I was confused by that at first. They can SLAM at 80, but that's a high SLAM FC level (more bleach). Not sure about the exact size of the pool, but it may help the whole process to do a partial drain - even a 1/4 - 1/2 drain, especially if it's a non-SWG pool. But if the owner is willing to maintain the FC of 31, to include the # of R-0871 drops that go with it, it's an option. I just like for folks to know their options. We'll help either way.