Hydrated filter aids, usable directly during continuous and vacuum filter processes, in association with perlite and/or kieselguhr. The addition of Fibroxcel Pronto range takes place without creating powder, therefore with the highest safety of the personnel charged with the product handling. Their particular formulation facilitates the conglobation in the perlite, used for the continuous dosing or to build the coat sheet on the rotating drum of vacuum filters. Fibroxcel Pronto 30: to be used as a precoat in brightening filtrations or dosed continuously with other agents to reach a particular brightness.