When you need just phosphorus, Phos 4 offers an easy, economical way to add this mineral to your horses diet. Provides 4 grams elemental phosphorus per ounce. Adding phosphorus is generally unnecessary unless your horse is eating only hay and upon testing, you've found that the Ca:P ratio is higher than 4:1 (four times more calcium than phosphorus). All sizes with Free Shipping in Continental U.S. (via UPS or USPS)* --- Supplemental Phosphorus for Low-P Hay Each one ounce scoop provides 4 grams of elemental phosphorus. Important Considerations Phosphorus needs to be balanced with calcium. Phosphorus levels in the diet should never exceed calcium levels. There should always be at least twice the level of calcium as phosphorus in the total diet. Adding phosphorus is generally unnecessary unless your horse is eating only hay and upon testing, you've found that the Ca:P ratio is higher than 4:1 (four times more calcium than phosphorus). Sizing and Prices All sizes with Free Shipping within Continental U.S. (via USPS or UPS) * see below All products are fresh and shipped directly from the manufacturer. Save 5% off of Horsetech's regular prices. 5 lb $39.85 (Regularly $41.95) 10 lb $58.85 (Regularly $61.95) 25 lb $134.85 (Regularly $141.95) Shipping Information * Phos 4 is shipped via USPS or UPS within 2 days of your order. Free Shipping is within the continental U.S. Shipping to Alaska or Hawaii may be charged separately. Please email [email protected] or call 940-487-7161 for exact shipping charges prior to ordering to these areas. Customers outside the U.S. are welcome to contact Horsetech directly to place an order. Interested in Auto-Ship? Send Getty Equine Nutrition an email at [email protected] or call 940-487-7161.