Add all at once in the case of epidemic mortality. A word of caution on SALT though. It should be food-grade or cattle feed grade, NON iodized salt. Brochis britskii cats, and native or wild caught Discus. Rams dislike it also.
Plants perish in the salt dose as listed above.
Do not use it if you have live plants. Note the divided dosing, so as not to add it all at once. They are safely dosed at a rate of one tablet dissolved per ten gallons water to be treated. The unique, carbamate-pesticide portion of this compound is the important adjunct that enhances it's parasiticidal effect. I also caution that there is significant toxicity of the Carbamates to certain fish, most notably Discus and Catfish, who may be affected adversely.