Scale problems are a common nuisance in heat pump systems and water heaters. Scale not only reduces the thermal efficiency of the equipment and increases energy consumption, but also may shorten the service life of the equipment. In order to effectively prevent scale formation, magnesium rods and electronic anodes have become two common solutions. In this paper, we will introduce the reasons for the formation of scale in detail and discuss the working principles of magnesium rods and electronic anodes as well as their advantages and disadvantages.

Water scale formation in water tanks

Causes of limescale formation

Scale is mainly formed by the precipitation of calcium and magnesium ions in water under high temperature environment. Over time, these minerals adhere to the inner walls of water tanks and pipes, forming hard deposits. These deposits can lead to reduced heat transfer efficiency and increased energy consumption, as well as overheating and damage to equipment.

Magnesium rods for limescale

How magnesium rods work

Magnesium rods (also known as anode rods) prevent limescale from being deposited in the tank by electrochemically bonding with minerals in the water. Specifically, the magnesium rods gradually dissolve in the water, releasing magnesium ions, which combine with the carbonates in the water to form soluble compounds, thus reducing the formation of limescale.

Application Examples

Magnesium rods are commonly used in water heater and heat pump systems to help extend the life of the equipment. For example, installing magnesium rods in water heaters can significantly reduce scale deposits, resulting in improved heating efficiency and lower maintenance costs.

Electronic anodes  rods for limescale

How electronic anodes work

Electronic anodes prevent scale formation by changing the crystalline form of minerals in water through the flow of electrons. The electronic anode generates a low-voltage current that causes calcium and magnesium ions in the water to form a non-crystallised suspension rather than adhering to the inner walls of the tank.

Application Examples

Electronic anodes are suitable for all types of water tanks and hot water systems. They are effective in reducing scale formation and perform particularly well in high hard water environments. For example, the use of electronic anodes in hard water areas can significantly reduce the frequency of equipment cleaning and maintenance.

Advantages and disadvantages of magnesium rods versus electronic anodes

Advantages and disadvantages of magnesium rods

Pros: lower cost, easy to install, easy to maintain. 

Magnesium rods are an affordable anti-scaling solution for most water heater and heat pump systems.

Cons: Requires regular replacement, limited effectiveness in high hardness water. 

Magnesium rods are gradually depleted over time, so they need to be checked and replaced regularly, and may be less effective, especially in hard water environments.

Advantages and disadvantages of electronic anodes

Pros: no need for replacement, suitable for a wide range of water qualities, low maintenance costs. 

Electronic anodes prevent scale formation through the flow of electrons, do not require regular replacement and are suitable for long-term use.

Cons:Higher initial cost, requires power support.

 Electronic anodes are more expensive to install and require a continuous power supply, which may not be suitable for some environments.