Quote Originally Posted by Real Genius View Post
Yeah, I'm a dive boat captain so I'm well familiar with it too. I don't think the fluid can be the connector AND the electrolyte. You need a complete circuit. Current will flow from the cathode to the anode (aluminum to copper in this case) through the fluid and return via the electrical connection. The electrical connection is usually physical contact between the two metals such as when a bronze prop is mounted to a steel shaft. I suspect a lot of pc cooling installations inadvertently ground the physically-separated metals like the blocks and radiators when it could be easily prevented. If they are both grounded, we have a return path and electrolysis can occur.
Not to argue but the field given off by most yachts even at anchor is strong enough to corrode the zincs on boats up to 150 yards away. This is a fact. The salt in the water makes it highly conductive--and the EM fields thrown off by charging equipment and the general wiring of the boat (as everything is bonded) is very powerful. That is why keeping the sacrificial zincs up to snuff is so critical--especially in harbor or when docked for long periods.

An improperly bonded or wired vessel can rapidly corrode the zincs on surrounding boats and lead to damage unless the situation is noted and remedied.

In a PC loop it is not exactly the same deal..but indeed the water acts as the electrolyte in that it makes the transfer of ions possible due to it's conductivity...this effect is independent of pump action or any other EM effect from the PC. It's like a battery.

Any easy proof. Dip a chunk of aluminum and a chunk of copper in some water and make sure they do not touch and take a voltage reading. To really make the point thow in a pich of table salt.