Maybe refit all the joints and connections in the right order, otherwise maybe the RO cartridge is duff.
what was the pressure going in , if its low ... 40 psi it may need booster to improve it mine goes in at 100 psi and i have the same readings as your chapChris
Hi MattIt's not a 50gpd from RoMan by any chance?
HI Matt.Does he flush regular, also Kirsty from Gardeners said to me about changing filters every 4-6 months, if i remember right the 3 were only about £20. May be his filters need changing.Macc
Spoke to a mate on phone, he said the same, how old are his filters?
If it's a reading from one of those 'orrible cheap in-line tds meters it might be worth checking against another meter.