Sitting full of water, Dex or pink plumbing
stuff? Run in salt
or fresh water (might as well do the raw water
side as well).
The short answer is "yes, a dilute solution of muriatic acid", but to what degree depends on whether the fresh water circuit was stored properly, how cold it got and so on. I assume in your part of Australia
, frost isn't a problem?
While you're at it, examine the zincs for wear and check out our friend Maine
essay on heat exchangers. Westerbeke / Universal Marine Heat Exchanger Photo Gallery by Compass Marine at pbase.com
It may help you to interpret what you may find.