After the formation of cores in the coagulation step, flocculant is dosed in order to transform these small core flakes into larger, stable flakes. The flocculant is often referred to as polymer or poly-electrolyte. The creation of flocculant has as its base a polymer in powder or a liquid concentrate from polymer. Polymer is a product that must be mixed with water, wherein clot formation occurs rapidly. After mixing with water, a certain aging time is necessary to “unfold” the polymer strand completly. Before the flocculant can be dosed, it must rest for a certain period of time (30 to 45 minutes). A flocculant control DVD can be used to measure the flocculant level.