I got you inbud. Go to the fish store and get Seachem neutral regulator. It is a phosphor buffer. Quote from bottle "It softens water by precipitating calcium and magnesium". Seachem does extensive testing and is renowned in the aquatic world for its science backing its products. I use it to adjust my water in my tank and sometimes to my plant water. Warning, This is a phosphate buffer so watch the amount of fert you use with it. Its also adjustable, one tsp may not eliminate all your calcium but it will bring it down a notch. Also I'll mention that this product was constructed around a planted aquarium so it should be completely harmless to plants though I wouldn't go too far above the recommended dose.