Just timed mine 1ltr in 10 seconds pumped tds 5, 1ltr in 20 seconds without pump tds 7. tds in 245.
That's from RO and before DI. Gaps water said it will take a few hours to run in the RO and I will get better TDS as I use it more for the first week. This appears to be happening. I can't see it going less than 7 or 8 from RO but most ROs don't seem to produce 000 hence need for DI canister.
Bit confused what you mean by that? That's producing pure for 650ltrs . Presume flusing is when valve is fully on with no pure being produced?? If so how often should I do that and for how long??