Specially designed for use in water treatment plants to correctly estimate the dosing of aluminum and such other coagulants for the treatment of water and sewage. In provides identical test conditions for all samples. The illuminated base consists of a fluorescent tube mounted below the translucent plastic plate to provide diffused cold light through floc samples. Flocculation consists of geared continuous run heavy-duty 1/20HP variable speed motor form 10-100RPM with built-in speed control SS stirring rods are provided with adjustable spacers to adjust the depth of stirring paddles. The shaft can be removed without disturbing other stirrers.