I've tried a few hydrated lime products, a small amount of BRS kalkwasser and I always go go to Mrs. Wage's pickling lime for the cost and it works just fine. The last stuff I tried, Graymont hydrated lime, was no good. Too high in something that cause excessive brown slime. Either dions, or more likely, chrysophytes. Limewater does not "self purify" and precipitate out all of the contaminates as claimed in many places. I found one single wastewater treatment reference outside of reefkeeping forums, and that's it. Even then, I try to keep my tank cleaner than a sewer. Lol
The effect does occur, but not sufficiently to just use any old calcium hydroxide product.