Over the last couple of years I've read several discussions about pickling lime vs aquarium trade kalk...bottom line seems to be that each is calcium hydroxide....pickling lime may be a bit less pure and it may leave more residue...but each properly applied seems to work. The cost difference is a major plus for the pickling lime.
I personally use Balls pickling lime and have for well over 18 months....a years supply is less than $10.00....and the product works fine....I add 1 tablespoon per gal of ro/di and let it settle a few hours. Then I drip it over night at a relatively slow rate...try not to use either the scum from the bottom or the scum from the top surface.
Any addition of kalkwasser can stabalise/maintain levels of calcium/alkalinity ... and does have the abality to precipitate phosphates out of the water column.
