Read it again , he asked if Inhibitor had ever been added when there is a pic of an empty inhibitor cantainer next to the F&E tank, I was not sniping at anyone, some inhibitors come with a label that you complete the date when installed and stick it to the boiler casing or the F&E tank , some dont so we leave the empty container next to the F&E tank so anyone else returning knows what is in the system, hope this clears things up for youA bit unfair looking at the start of the thread it was Derekoo who tried to be helpful with a few suggestions which ianmcd started sniping at him with post 5 with gas112 jumping on the bandwagon in post 9. Derekoo then gave as good as he got if not better. Hopefully the OP will come back with the the outcome of the resulting investigations and all will be the wiser and someone will have guessed right which looking at the number of previous postings should be ianmcd closely followed by gas112 but you never know?