Electrolytic Corrosion In Swimming Pools - Calorex VARIHEAT VH3 AA600 Manuel D'installation

2.4 ELECTROLYTIC CORROSION IN SWIMMING POOLS

Electrolytic corrosion will occur when dissimilar metals that are in contact with each other create a potential
difference between themselves. Sometimes separated by a conductive substance known as an electrolyte, the
dissimilar metals will create a small voltage (potential difference) that allows the ions of one material to pass to the
other. Just like a battery, ions will pass from the most positive material to the more negative material.
Anything more than 0.3 volts can cause the most positive material to degrade.
A swimming pool with its associated equipment can create this effect. The pool water being an ideal electrolyte
and components of the filtration circuit, heating system, steps, lights etc providing the dissimilar metals needed to
complete the circuit.
Whilst these small voltages are rarely a safety threat, they can create premature failure through corrosion. Not
dissimilar to corrosion through oxidation, electrolytic corrosion can cause complete failure of a metallic material in
a very short period of time.
In order to prevent this type of corrosion all metallic components in contact with swimming pool water should be
bonded together using 10mm² bonding cable. This includes non-electrical items such as metal filters, pump
strainer boxes, heat exchangers, steps and handrails. It is highly recommended that bonding be retrofitted to
existing pools, which may not be protected by this system.
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