Several empirical equatioas used in the modeling of up flow pebble bed floculation are examined. Experiments carried in a reduced scale model using two different types of water allowed to develop an equation for optimal designs in local conditions in Medellin, Colombia. Goodness of the system is confirmed by turbidity remolion efficiency under certain design parameters. By experimentation adequate equations were chosen to fit results obtained in the reactor, particularly those used to calculate head losses. Recomendations on those parameters are made to obtain maximum reactor efficiency.