"Aidan" wrote in message
om...
What is the best inhibitor to use in this sort of system anyway? I was
going to get some more Fernox MB1 but it's a bit pricey (£19/4l).

No idea, I don't know what's in any of them. I use Fernox or Sentinel.
Corrosion is cheaper, in the short term..

Sentinel X-100 is far cheaper and just as good.