The recommended dose rate for Cool Puck is one 53gram puck for 20.000 L of water, wich translates to a theoretical maximum dose rate of 2.65 mg/L. All of the above (see page 2 PDF- schedule) toxicity results are greater than the recommended dose rate. C. dubia was the most sensitive organism to the product, with an acute effects level approximately 16-fold above the product's recommended dose rate. The acute Lethal Concentration (LC50) value for C.dubia was lower than the chronic Inhibation Concentration (IC25)value, suggesting that the toxicity of the product may be ameliorated by solids or dissolved organic matter in the aquatic matrix (i.e., such materials ate added as food in chronic test, but not in the acute tests). Effects levels for acute rainbow trout and chronic fathead minnow tests (IC25 basis) are approximately 66 and 94 times the recommended dose rate, repectively.