Luc, presuming your hydroforce is 1:8 dilution the logical thing is to use 8x the stated dilution for a pressure sprayer (120ml per litre of water in your hydroforce container). However because you tend to put a bit more down with a hydroforce you really don't need that all the time. Mostly I'll use around 80ml per litre but sometimes as much as 150 if it's a minger.