96%; Calcium Carbonate Excellent source of fast-acting calcium and carbon for use in irrigation systems (flood, sprinkler or drip) and for foliar feeding. This limestone is screened to an ultra-fine 325 mesh for easy mixing with water and quick uptake by plants and microbes. Use at 10-100 lb/acre in irrigation water or 1-10 lb/100 gal as a foliar, with multiple applications of up to 10 per season. Solution grade limestone is also useful for cleaning algaes from water lines and emitters. Can also be broadcast and watered in.