A method is described that includes contacting an olefin with a catalyst in a polymerization reactor, polymerizing at least a portion of the olefin to form an alpha olefin reaction product, detecting a condition within the polymerization reactor, determining an average temperature of at least one olefin product particle based on the condition, determining an operating particle temperature threshold using a foul curve, comparing the average temperature of the polymer particle to the operating particle temperature threshold, changing one or more operating parameters in response to the comparing, and maintaining the average temperature of the olefin polymer particle at or below the operating particle temperature threshold in response to changing the one or more operating parameters. The alpha olefin reaction product includes a plurality of olefin polymer particles, and the polymerization reactor includes a reaction mixture that includes the olefin, the catalyst, a diluent, and the alpha olefin reaction product.