What descaler for my boiler

[Ratboy67]

I've got an electric boiler in the loft with integrated cold feed tank on top which supplies downstairs kitchen sink and bath (don't know what it's called officially, (only that it's made by Castle). There's a load of scale in the cold feed tank which I assume is similar case in hot water tank underneath. I can't fill a bath in one go (tap stops and have to wait 15 mins before turning tap on again) so want to try a descale but a bit confused by variety of descalers available. Thinking of trying Fernox DS3 limescale remover. Also once descaler is in tank can it be emptied through the taps to descale pipes or should tank be emptied independently?

Any advice much appreciated! Thankyou

 

[oilman]

You'll need an acid descaler, but it will also have a go at the copper. Not a lot maybe, but it sounds like the boiler will be quite old. In this case it's probably time to look at a new one, and use something like a combimate to reduce the scaling in future.