New at using RO/DI machine, need help

[CaptNemo]

Hello everyone,
I recently purchased a new Rodi machine from one of the sponsor here on Reefcentral and has been using it for like 3 times. The first time, I used TDS meter to measure the purity of water and it was 0ppm. I didn't check the second time but i check the third time and it was 3-4ppm.
what is going on?
Here are the step that i have been using my rodi machine, please tell me if I use it correctly or not
1) put rodi outlet into my rodi water container and put waste outlet into the washing machine.
2) turn on the water to the Inlet.
3) After i get enough water, I just turn off the water to the Inlet and leave the machine there.
The next time that I need more rodi water, I just turn on the water to the Inlet and get let it runs

Is that the correct way of using the machine or should i be doing something else also?
My Pressure is around 70, is that normal?

Please advise me on how to best use and keep my machine in top condition.

Thanks,

[1badbrd]

if you dont let the water bypass the restrictor before starting to fill the storage container then there is some TDS creep that might flow into the storage container which would give a little TDS %.

I found this out a lot on a float valve, so every time i used a little water from the storage tank the TDS that was left in the line went into the tank. Now i bypass the restrictor and let it flow 100% into the drain for a couple minutes, then send it through the restictor which is 0PPM

Might need to flush it before filling up tank

[AZDesertRat]

Do not test the TDS from the storage container. Use a squeaky clean clear drinking water glass with absolutly no water spots or soap residue as they can skew the readings. Always triple rinse both the glass and meter in DI water after each use and store the glass upside down to keep dust out.