Just want to reiterate about rinsing. I have dipped many times with Bayer without problems, but the last time I dipped a large piece of rock with zoas for nudibranchs and rinsed multiple times, but clearly not enough. All 3 of my shrimp, fire, cleaner and coral banded, died as well as all my pods. Moral, when you think you have rinsed enough do it a few more times.