Just did mine with Rydelime, we disconnected the hose to exhaust elbow and just put a hose into water intake bowl, connected 350gph bilge pump in line and recirculated for 1.5 hours and then flushed with fresh water, don't forget to remove the impeller !
The mix should be a 50/50 solution , we put a snail shell into a test sample and watched it fizz away to nothing, amazing stuff,
saw a bulletin from Volvo who recommend using this stuff
They sell it at the chandlers in Cobbs.
Mick