basicalywhy limit yourself to a few hundred litres per day, what if your water is turned off for a while?  We started with a 200gpd ro and have 50psi tap pressure, only produced around 250/300ltrs per day so it had to run 24hrsa day 7 days a week, thus meaning the outside tap was always in use.  It was no use if we needed to produce water fast for a busy day,  I just wouldn't limit myself, besides how much more does a merlin cost?  A 300gpd from ro-man is 265 so a merlin proding 720gpd is only another 35quid.