Yup I use them, although I'm not sure how important they are. I couldn’t get calcium chloride and sodium bicarbonate which had an analysis of impurities cheaper than the balling lite calcium, bicarb and magnesium a couple of years ago so I bought them, and since a friend was using the balling lite 'method' with fantastic results I got the 3 bottles of trace elements at the same time. When I mix up new calcium and alk I add the required amounts of the 3 trace bottles. I suspect that in a tank with more calcium carbonate turnover they might be useful but at the level I am using calcium and alk I can't see them making a difference. To me this is just Randys 2 part with some trace elements added. What do you want to know about them?