I wanted to post this in case it saves someone else this headache in the future. I started a new 75gal, fully planted with 50% old water and old bio media. It fully cycled in 48 hours. I added BN Pleco, waited two weeks, then moved one 2 year old Ryukin over to test if the plants were established enough to resist being pulled up before adding a larger Ryukin. Waited two weeks, by which time I had serious green hair outbreak. I began adding Excel at a rate of 7.5ml every 24 hours. Here's the cautionary part. The Ryukin began sitting on the tank bottom refusing to eat after three days of excel. I tested water, and all was perfect. I adjusted water flow thinking maybe it was to strong and stressing him. Waited 2 days, no change. The Excel was the only other variable. I only change one thing at a time just for reasons like this, so I can tell what causes problems without sorting through 10 variables. I stopped dosing Excel and she responded by being 50% more active and eating again within 24hours. In 48 hours she was 100% back to normal.