06-08-2021, 09:42 AM
The information on the web suggests that Fernox F1 should be right for iron and aluminium. Possibly your water in that area is soft with a relatively low pH. I suggest that distilled water is best. Water from a dehuidifier is effectively just that, or you can use water from defrosting the fridge or freezer. If the deposit is soft as you say, power flushing with a hose alternately in each engine connection on an annual basis will probably clear the system usefully. I have to admit that I do not worry unduly about my cooling systems unles there are signs of a problem.