If you are experiencing frothing in the developer, make sure the tank and reel are cleaned properly after using Photoflo. You can switch to Edwal LFN for final rinse, uses less product and rinses clean with warm water for clean up, it can also be used in the developer to de-foam. You also should mix developer with bottled water to insure no entrained air in the water, or allow time for air to settle out.