TDS Reading

I currently just have an RO system, but I have a bolt on DI canister and filter on it it's way. The water straight from the tap is 45ppm, once through the RO unit it's 5ppm. So is 5ppm acceptable until my DI arrives, or is that too high?

 

5 is pretty high but probably acceptable in the short term. Since your tap TDS is only 45 to begin with its pretty safe to assume you have very good tap water, the national average is closer to 250 TDS.

Your membrane is not very efficient though if you are putting 45 in and getting 5 out, thats only 88 or 89% rejection rate or removal efficiency. It should be more like 96 to 98% efficient with a RO only TDS of 1 or maybe 2 at most. My tap TDS is 630 and my RO only TDS is juet 3 and of course the RO/DI is 0 TDS.

 

Thanks for the reply AZ. I'm currently in Brunei, so I'm amazed that the TDS reading is so low. Unfortunately my choice of kit is limited so I had to buy my RO unit locally. The good thing is it does come with a 60psi booster and a flush valve, but I'm guessing the membrane will be a cheap one, hence why such a low rejection rate. But if the DI unit can remove the last 5, then I will be happy