A microparticle system for use as a retention and drainage aid in the production of alkaline and acid paper products comprises a high molecular weight flocculant polymer (6) and a silica-acid colloid blend (7), and optionally a cationic coagulant or a medium molecular weight flocculant (5). The high molecular weight flocculant polymer (6) may be added to the furnish after the fan pump (1) and prior to the pressure screen (2); the silica-acid colloid blend (7) may be added to the furnish after the pressure screen (2), and optionally, the coagulant or medium molecular weight flocculant (5) may be added prior to the fan pump (1). Addition of the microparticle system to the paper furnish improves retention and drainage during the papermaking process and sheet formation. The acid colloid of the silica-acid colloid blend (7) is a polymer or a copolymer of a melamine aldehyde acid colloid.