Bridgewell Agriculture Calphos™ AFERPHGRACAP2KB Granular Soft Rock Phosphate 2,000 lbs - Calphos™ is an environmentally safe natural source of soft rock phosphate and calcium. It provides all of the benefits of calcium and phosphorous without the handling problems. Calphos™ granulating process allows for clean, nearly dust-free applications while being non-toxic and non-corrosive.