Can someone tell me if it's okay to use garden lime as a source of calcium? The ingredients are; calcium carbonate as elemental 22%, calcium carbonate 55%, magnesium as elemental 10%, magnesium carbonate 37%, calcium carbonate to equal 96%. The calcium level in my water from the tap is 5.9 ppm and in my tank the kH is 2 degrees. Jennifer in HOT B.C.