Calcium Soluble is a 100% pulverized limestone calcium carbonate powder that raises calcium levels in hydroponic and soil systems without adding magnesium. Its high calcium content and very low magnesium make it superior to dolomitic lime when soils are already high in magnesium. At a glance Type: Pulverized limestone calcium carbonate powder Elemental calcium: 38% Calcium carbonate equivalent: 95% Magnesium: Very low, ideal when soils are already high in magnesium Particle size: 97.0% passing at 100 mesh, 85% passing at 200 mesh for quick dispersion Form: Fine, easy-to-dissolve powder for soil mixes and hydroponic solutions Best for Hydroponic systems needing a pure calcium source Soil gardens and raised beds where magnesium is abundant Fruiting crops, tomatoes, peppers, and leafy greens Container gardening and potting mixes How to use Mix the fine powder into soil and potting blends or dissolve into hydroponic solutions to deliver a concentrated calcium boost. Its fine particle size supports quick dispersion and steady calcium availability without altering the soil's magnesium balance. About The Soil Makers The Soil Makers provide mineral amendments backed by hands-on soil science to support strong roots, sturdy stems, and better nutrient uptake indoors and out.