Natural Chemistry Phosfree Commercial 3 Liter Reduces Extremely High Level Of Phosphate P/N: 05236 PHOSfree Commercial Strength: High Powered Phosphate Removal "PHOSfree" is available in commercial strength. It is the only patented product that removes phosphates on the filter. This commercial strength formula quickly reduces extreme high phosphate levels. PHOSfree Commercial Strength provides professional service companies an excellent tool for reducing the time spent trying to lower very high phosphate levels reliably. It will also work well on large commercial and institutional swimming pools.