Tsp stands for teaspoon, btw. Just wanted to let you know that tap water is full of chlorine that kills most of the Great White bacteria that you paid a lot of money for. To fix this problem, just fill it up and wait 24 hrs with no lid. The chlorine will evaporate. Chlorine hurts your root growth. I have 10 milk jugs full of water sitting on the floor. I have a filter system. But, I want to make extra sure it's safe. I have Great White, but I prefer Recharge bc it has kelp and molassis added to it and it works faster. I've tried four different brands. Recharge seemed to work the fastest.