Hi Alan,i also run the merlin as you know,iv`e read that the trouble with the merlin is that it doesn`t bring down the tds readings aswell as other ro`s,unless you add a booster pump,but this reduces the life span of the membranes,but it does produce about 3000 litres aday as standard,im quite happy with the way mine runs,but i would like to know myself what other ro`s are reccomended,Gaz.