So just what is it that my tank needs! If Julian can tell that without some major water testing of my tank, he's in the wrong business! I use the following as my guide to adding anything to my tank except kalk. I have a 180g tank, lightly stocked with coral and fish, zero crowding of corals. Every 3 months I get over $100 worth of store credit at the LFS taking in frags, sometimes as high as $200. The only thing I've ever dosed is kalkwasser and do a 25 gallon water change each month. The tank has been up for over 2 years and coralline growth is ridiculous, corals calcify at a very nice rate, and soft corals love it. An example of calcification rates. 18 months ago I added a bud from a frogspawn, about 1/2" in diameter. In 18 months it has grown to over 30 heads with the skeleton about 6" in diameter. My Trumpet corals grow from around 20 heads to around 60 heads in 8 months, at which point I cut them in half and let it start over. Save your money!!!!!