Make sure there isn't copper in the algae wafer ingredients. I feed Nutrafin Max Spirulina Algae Tablets - but they have been harder and harder to find. They are 100% vegie. I smash them in a paper towel with the handle of a knife..then pour it in the tank. I also microwave sweet potato, cool it down, and scoop a piece out of the middle for the shrimp. Also, Nutrafin Max Spirulina Flakes, but those arent 100% vegie.