Update
Added about 4 to 5 litre jugs of resin. Cylinder now 90% full.
TDS after 15 minutes of running through the DI is flickering between 2 and 1. After always having zero I find this a little unsettling, especially as this is new resin, and the pre-filter was only changed a couple of weeks ago.
TDS from tap is the lowest I've seen it at 253 (could this be down to the hot weather).
TDS in the tank after RO is 48.
TDS in several different clean cups between 1 and 2.
Is it possible that this will sort itself after a bit more water passes through it? If not what can I do?
As always, thanks