I need to add inhibitor to my CH system as there's been a leak in it for over three months. Is it okay to add inhibitor by unscrewing the Magnaclean, taking out the excess water and filling it with inhibitor? This approach would be far easier and less messy than adding it through a rad.
Also, which inhibitor should I go for and how much would I need? It's a sealed combi-boiler system with 8 rads.
Also, which inhibitor should I go for and how much would I need? It's a sealed combi-boiler system with 8 rads.

