I personally just started using the bright well kalk +2 just to give it a try. I wanted to use it a year and a half ago when I started dripping kalk, but I was scared away because alot of people said the mg just precipitates out of it. Using regular kalk, and when I had the money to test mg every couple days, I noticed no added stability in the mg department. Ive been using kalk+2 for about 2 weeks now, Ive been doing water changes with oceanic salt for mg dosing every 2 weeks due to my financial situation. for the last couple months as I burned up my last mg test kit, I noticed color differences in my acros due to mg deficiancy, witch is how I judge if I need mg right now, and in 2 weeks I see the change and use the oceanic salt to correct it. Now that ive been using the kalk+2, the apparent bi weekly mg deficancy seems to be a thing of the past, and I might change to monthly water changes if this keeps up. They use it at one of my lfs's and the owner said he's used it for 2 years now and vs regular kalk, it cuts his need to dose mg. in about half, not exactly the perfect ratio that the packaging promises, but there is definatly a significant increase in mg stability when using it. adding to that the fact that its only $2 more a lb. on average, and in my situation it nearly eliminates my need for additional mg. and if I was still testing for it, it would cut my need to test in nearly half (would save about $15 every month and a half plus the cost of mg supplement) I think Im gonna stick with it.