Dosing Pump Guide
How peristaltic dosing pumps deliver precise volumes of liquids, why they suit reef and planted tanks, and how to calibrate and maintain them.
What it is
A dosing pump is an automated peristaltic pump that delivers precise amounts of liquid — fertilizers, trace elements or supplements — on a set schedule, removing the inconsistency of manual dosing.
How it works
A rotor carries several rollers or wipers around its circumference that compress a flexible tube as they turn, pushing fluid forward in a peristaltic wave. A fixed amount of fluid is pumped per rotation, which allows the volume delivered to be metered accurately. The pumped fluid contacts only the inside surface of the tubing, so it never touches the impeller, seals or valves.
Why peristaltic suits aquariums
- The mechanism never contacts the fluid, which matters for caustic or precipitate-forming liquids such as calcium hydroxide (kalkwasser)
- It is self-priming and can lift fluid from a reservoir
- It can run dry indefinitely without damage
- Its design prevents backflow and siphoning without the check valves that often fail in other systems
Types and variants
Pumps may have one or several independent heads (channels), each dosing a different liquid such as the components of a two-part calcium and alkalinity supplement, trace elements, kalkwasser, top-off water or planted-tank fertilizers. Flow can be tuned over a wide range, with fine dosing down to roughly 1 ml per minute.
Calibration and use
Because the volume per rotation is fixed, the pump is calibrated by measuring the output over a known run time and adjusting the schedule to deliver the daily target. The dosing rate is fine-tuned over a wide span, from very small amounts on the order of 1 ml per minute up to much higher rates, so the same pump can handle both a tiny trace-element dose and a larger top-off. Splitting a daily dose into several small portions spread through the day keeps parameters more stable than a single large addition, which matters in reef tanks where calcium and alkalinity must track plant or coral uptake closely.
Maintenance
The flexible tubing degrades with time and requires periodic replacement; worn tube reduces accuracy. Inlet and outlet lines are kept free of kinks and crystallized residue, and dosing is re-checked after a tube change because output can shift.