RO/DI question/help high TDS reading?

[pillowfish]

Yup...me again <sigh> I have a 6? stage RO/DI unit(125gpd), works great!-then I got a TDS meter. The water first tested at 400+ after a couple of hours of bleeding the line and cleaning the water storage container(clear plastic storage container w/ float vale) the reading was down to the low 100's
I have never changed membranes on units(this is my first one) Found a few human errors..adjusted a few thiings and the reading was slightly less. The canisters are not clear and quite frnkly I am not sure exactly I'd know where to start on changing membranes out or DI resin. The DI resin was orange when I bought it and was told that was the "normal" color it would turn a different color when it was time to change them out. My water here in the apt tests at around 200ppm-the output line is reading in the 400"s+. So wherre does one start?
I have tested the water bypassing the container(just checking), no real difference, and not exactly sure where the line is that goes from the RO portion to the DI to bypass the DI to check the filters? And is there a way to check each membrane individually? Just for clarification, the unit has not been used "enough" IMO that the membranes need changing-but if they do recommendations on which ones to get? type of membrane? I believe they are univeral for the most part but the unit is dvoned systems RO/DI unit, if that helps any....

 

[MikeG]

I would start by disconnecting the DI and testing after RO. You can also replace the sediment and carbon filters right away as they are inexpensive. You should have a very low reading after RO if your input TDS is around 200ppm. You are sure all the connections are correct yes?

 

[pillowfish]

I would start by disconnecting the DI and testing after RO. You can also replace the sediment and carbon filters right away as they are inexpensive. You should have a very low reading after RO if your input TDS is around 200ppm. You are sure all the connections are correct yes?

I have not tested the water yet by bypassing the DI stage of filtration(making sure I know which is which to put back together later). I am not 100% sure if all the connections are correct..I bought the unit from another member who previously set up the RO/DI and RO reservoir with the float switch. All I did was connect the water line from the unit to the washing machine via a "Y" connector(my term for it) and have the waste line draining into the waste water line for the washing machine as well. Up until I swapped the float valves out-the unit has stayed untouched from original purchase. Looking at buying new filters now..any recommendations?
tahnks!

 

[Richard]

I would look at you pre filters and change if it looks dirty.

If the pre filter is dirty I would go ahead and change the carbon.

If your reading out of the RO is high (without the DI install)then you will need a RO filter.

I would first test the water out of the tap. What ever the TDS reads the out put of the RO (w/o DI) should be around 90-95% LESS than the tap. Then the DI would remove the rest or should be in the very low single#s. If it does not then you will need a DI cartrage.

BTW how old is the unit?

 

[Richard]

I forgot to add. IME when the DI resin needs changing it'll turn orange. Mine are blue and turns into orange. It just may be different type.

 

[pillowfish]

...Just wanted to say thanks for everyone's advice/tips/suggestions, etc... I'm FINALLY happy to say problem solved and fixed Without creating new problems I tested each stage of the RO/DI independently and finally found the source..the first membrane on the RO portion itself was "blown"? TDS after just the RO portion the unit was in the 400's, water tested after passing through RO unit followed by the DI portion(resin) was around 110 or a bit less. SO I will go under the assumption that the information on the DI resin coloration is correct and start with just replacing the membranes in the RO phase itself and see if that does the trick. Now off to search for replacements! Thanks