On my 2017 Berlingo van I use this every month. Great stuff and if you shop around you can get it for approx £8 a bottle. On the Citroen it has an extra tank of DPF cleaner approx 1.6 litres attached to the diesel tank and when you open the fuel flap it squirts some into the diesel tank. All very good but at £60 odd a litre it is very expensive and a right pain to refill.
My tank and pump went on me so £180 for a 1.5 ltr plastic tank and pump but no additive! Purchased 1 ltr of the additive and topped the remaining up with this Mannol fluid. No problems 2500 miles later and its running as sweet as a nut.
If you read the bottle Im sure it says add a little every 6 months or so but as I use a varied brand of supermarket and branded diesel I like to keep on top of it.
https://www.amazon.co.uk/Mannol-Dies...40600067&psc=1