I am on a quest to find a local source of calcium hydroxide at a good price in Austin and I have been stumped trying to find pickling lime in my area. A local Fiesta Mart manager pointed me to "Cal Mexicana" and he told me that it was food grade lime that that was used to make tortillas. It looks like lime to me but I am apprehensive about trusting the word of a grocer (however knowledgable) with the health of my aquarium. Can anyone confirm that this is, in fact, calcium hydroxide before I give it a try? At $.99 for a 4 oz bag this may be a good substitute for $20 / lb Kalk mixes.

Thanks!

Jason