Electrolytic Corrosion In Swimming Pools - Calorex Pro-Pac Series Owners & Installation Manual

5.0 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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