I was looking for that info, but missed it. Thanks.
A teaspoon is 1/6 of an ounce, which is about 4.5 to 5 grams. The normal dose is around a quarter of a gram. Yep, 15x overdose, more or less. Maybe they even took a heaping teaspoon.
Not to mention that the aquarium product is probably supposed to be diluted in 50 gallons of water.