Is inhibitor required when refilling the cylinder

Sorry if this has been asked before, but I can't find an answer.

I have a Pulsa coil III and need to replace one of the immersion heaters. When I refill the cylinder do I need to add an inhibitor like Fernox etc.? Looking at the Gledhill manual there is no mention of it.

Thanks.

Hi

You can if you want to.
1 bottle to ever 100 litres

So 150 litres = 1.5 bottles

I would put both bottles in.

Mike