New RO/DI Unit

I just received an RO/DI Unit, it is brand new and never have been used, I have never had a new one before, so how much water do I usually have to waste before the unit starts to produce good water? I know that I can use a TDS Meter, but do I need to waste water first before the water starts being good to use for my tank? Thanks in advance.

 

You need to flush the filters initially for best performance and component life.
Start by disconnecting the 1/4" line which leads from the carbon up to the RO membrane at the membrane end and stick this in the sink or a bucket. Next remove the carbon(s) from their housings and screw the empty housing sumps back on. Now connect the water supply and run several gallons of water through the prefilter to rinse any binders or glues left over from the manufacturing process. Shut off the supply and install the first carbon if it has two and do the same to purge any carbon dust or fines so they don't foul the downstream carbon or the RO membrane. If it has two carbons do the same with the second one next.
Now the prefilter and carbon are clean so reconnect the 1/4" line at the membrane. Now, very important, disconnect or remove the DI filter. Run 3 to 5 gallons through the system, this will take some time depending on the GPD rating of the system, your water pressure and water temperature. A TDS meter is nice here since it will tell you when your TDS has dropped to an acceptable range, usually 96 to 98% removal of the incoming tap water TDS. Finally install the DI filter and do a final rinse of the resin, usually 2 or 3 canister volumes should do the trick and you are ready to make RO/DI water! Good luck and Happy Holidays.

While you are doing all this you may want to get some baseline readings on things like your water pressure and water temperature, calculate your GPD output and most importantly calculate your waste ratio to ensure it is in the recommended 4:1 range for best membrane flushing and lifespan.