So what is the maximum amount of calcium hydroxide you are using per gallon (in teaspoons)? Kent Marine says no more than 2 teaspoons/gallon. Even at that dose I am not getting any settling at the bottom of the container.
You can mix slightly more with very cold water but at room temp 2tsp should be about all you can dissolve into a gallon of water. If you add vinegar you can dissolve a little bit more. There is no harm in adding more but it's not going to dissolve.
Straight from your local grocery store. While you are there pick up some Mrs. Wages pickling lime for 2 bucks a pound instead of paying 15 a pound for the same thing.