RO/DI unit testing and questions

[InfernoST]

Hi Gang
I got my RO/DI unit yesterday and started performing some tests on it. I hooked up the unit and flushed it for 1/2 hour then shut the flush valve and let it run for another hour as per the directions. The first test was checking the TDS value of the tap water. Connected the water feed directly to the DI unit which has the TDS meter mounted to it and turned the water on (I'll get a picture of this test on the next installment)and the reading was 035 PPM on the input and 000 PPM on the output (Also reversed the input and output sensors to check the validity of the meter, The 035 PPM remained on the output side whether the input or output sensor was on the ouput side ). The next step I connected the first 4 stages, then from the output of the 4th stage connected the 5th stage (DI unit with the TDS meter) and took some readings. After the 4th stage the TDS was knocked down to 004 PPM and the output of the 5th stage was also 000 PPM. Here are the pics for this test.

Input value after 4th stage


Output value after 5th Stage (DI Unit)


I'm going to perform 1st test again with photos, along with testing straight tap water, RO/DI waste water, and actual RO/DI water with the test kits we use and post the results. My question now is why is the output of all 5 stages the same as just going through the 5th stage only (DI unit with TDS meter)? Another question is according to the TDS meter what is your opinion about the quality of the water in Brooklyn?

[m3drver]

Your RO/Di unit should have a Membrane and some prefilters ( carbon and sediment filter). the prefilters will remove the larger particles in the water ( I'm talking microns here) the membrane will usually catch 95-98% of all other TDS. The DI resin takes care of the 2% giving you pure water 0 TDS.

If you run the your water feed just through the DI resin it WILL give you 0 TDS but your resin will not last long at all. You are basically asking the DI to do the work of the membrane and prefilters you will find yourself replacing the resin quite often , which can get expensive.

I lived in brooklyn a few years ago and I have been told that NYC has very good water. 35 PPM TDS is pretty darn good. Here in Jersey I get ~126 TDS.

Last year the township I live in flushed the water pipes in my neighborhood. the TDS in the water after the flush ruined the Membrane and prefilters. I didn't catch it until I found myself replacing the DI resin after only 60 gal of pure water. After replacing all the prefilters, membrane and resin I 've made countless gals of pure water and my DI resin and filters are still going strong.

Hope this helps

[InfernoST]

Originally Posted by m3drver

Your RO/Di unit should have a Membrane and some prefilters ( carbon and sediment filter). the prefilters will remove the larger particles in the water ( I'm talking microns here) the membrane will usually catch 95-98% of all other TDS. The DI resin takes care of the 2% giving you pure water 0 TDS.

If you run the your water feed just through the DI resin it WILL give you 0 TDS but your resin will not last long at all. You are basically asking the DI to do the work of the membrane and prefilters you will find yourself replacing the resin quite often , which can get expensive.

I lived in brooklyn a few years ago and I have been told that NYC has very good water. 35 PPM TDS is pretty darn good. Here in Jersey I get ~126 TDS.

Last year the township I live in flushed the water pipes in my neighborhood. the TDS in the water after the flush ruined the Membrane and prefilters. I didn't catch it until I found myself replacing the DI resin after only 60 gal of pure water. After replacing all the prefilters, membrane and resin I 've made countless gals of pure water and my DI resin and filters are still going strong.

Hope this helps

Thanks man. Your explanation helped a lot. Now I understand. You know what's funny my brother inlaws live in Manalapan NJ and they don't use their tap water for food prep or drinking just showers & Laundry. They buy tons of bottles water for drinking and food prep. I tell them they never should have left Bensonhurst because we have the best food (If you love italian) and consumable water.
What's your take on using the waste water for the plants and such because it seems to be a 3 to 1 ratio which adds up quickly?

[m3drver]

Originally Posted by InfernoST

Thanks man. Your explanation helped a lot. Now I understand. You know what's funny my brother inlaws live in Manalapan NJ and they don't use their tap water for food prep or drinking just showers & Laundry. They buy tons of bottles water for drinking and food prep. I tell them they never should have left Bensonhurst because we have the best food (If you love italian) and consumable water.
What's your take on using the waste water for the plants and such because it seems to be a 3 to 1 ratio which adds up quickly?

Yep, we too only drink filtered / bottled water. Jersey water is just plain dirty Anyhow the waster water on the other hand should be ideal for your plants/garden and for cleaning/washing stuff. My waste water goes down the drain. I would NOT use it for personal consumption like cooking since it has all the impurities that was just removed.

Hope this helps

[InfernoST]

Cool, then waste water will become garden water. Thanks again