I've got a couple of questions for all of the experts. 1. Is it possible to test for Potassium levels ? I've looked but not found a test kit. 2. What are the dosing recomendations for the following. Potassium Gluconate Potassium Sulfate Potash K2O 3. What are the effects of overdosing an aquarium if a dosing mistake is made. Thanks for all the great info Ken Whelan