Greetings. Just in case this happens to someone else-- Post-Harvey biblical rains I began a preemptive SLAM. My CYA had dropped to 30 from 40 pre-storm. From that point I kept noting extreme daily loss of FC and figured I had occult algae growth. CC averaged 1.0 - 1.5. Water became crystalline fairly quickly. Continued SLAM. One week into SLAM I ran another CYA: below 20, probably way below! Once I restored CYA, daily FC loss stopped. Lesson: keep checking that CYA . Best of luck to all Harvey and Irma members.