The LiterMeter III is an automatic precision dosing system for the aquarium industry. Three independent programs control one built-in pump and up to two external pumps. Perform 2-way water changes, in addition to eliminating the manual drudgery of dosing Kalkwasser, trace elements, or topping off evaporated water. Quiet operation, auto-calibration, and virtually maintenance-free. LiterMeter 3's are precise top of the line automatic dosing systems. They can be used with other Litermeter accessories to perform a variety of reefkeeping chores such as 2-way water changes, top off, and 2 part dosing. LiterMeter 3's are made out of precision-machined aluminum fabricated to exacting aerospace tolerances. The outer surface is polished to a mirror finish. The pump's planetary direct drive is at an 11:1 ratio, thus providing enough torque to generate over 40 pounds of pressure. This incredible lift enables the LiterMeter IIITM to pump over 60 feet above itself at a flow rate of over 250 ml/min. It can also draw up from 25 feet below. The motor in the LiterMeter IIITM is custom-designed by the premiere U.S. manufacturer of precision high reliability. Calcium maintenance and alkalinity control are essential for a healthy reef tank. SpectraPure's LiterMeter IIITM eliminates the manual drudgery of dosing Kalkwasser, trace elements, or topping off evaporated water. Kalkwasser replenishment, to be most effective, should be added to the aquarium slowly and consistently to avoid precipitation of calcium carbonate. The LiterMeter IIITM automatically and reliably performs this task. The LiterMeter IIITM offers features found only on expensive laboratory pumps. Built-in calibration features eliminate the guesswork of un-calibrated competitive units. Unlike noisy industrial metering pumps sold to the aquarium trades, SpectraPure's LiterMeter IIITM was specially designed for critical aquarium dosing and is so quiet you can use it in your living room. Improved three-roller direct-motor drive eliminates noisy gears and improves flow accuracy and tubing life. It can be run dry without damage. Three independent programs control the internal pump, as well as two optional external pumps. The LM3-RPM is a LiterMeter IIITM pump mounted in a small plastic box.