i have this: http://search.stores.ebay.co.uk/Aqu...sopZ1QQfsubZ17035217QQsaselZ705729236QQsofpZ0 but i cannot work out how to adjust ther pressures? (psi and BAR?) well the both say psi! they are both at 50 but i think, arcording to the tutorial on here, i need to get the smaller dial to about 20psi, while leaving the top at 50. i think 20 psi is a bout 1.5 BAR. i need heeelp!