I have used Mrs Wages since 2004. Currently I mix ¾ of a teaspoon per gal of water for the ATO. It holds ca to 430-440 and alk to 8.8 to 9.0. The tank is a 150 gal mixed reef. Evaporation is about 4 to 5 gallons a week. I started at ¼ teaspoon and worked up every week until the ca / alk were increasing, then backed off.