You can pucrhase chemical inhibitor on our website here.
The simplest way to add inhibitor to your central heating system is via a heated towel rail, however not everyone has a heated towel rail in their home, which requires you to find an alternative method.
In this video, James the plumber shows you the process of adding inhibitor to your system via the feed and expansion (F & E) tank in your loft. It's a relatively simple method, but it does require you to clamber in and out of your loft to be able to do it.
James gives you some tips on what to do and how to make sure your tank is kept clean.
Adding inhibitor to your system is very effective in stopping corrosion in your radiators. One bottle of inhibitor will be good for about ten radiators, so it's really worth the effort.