ro/di question

[riche]

I changes some filters around on my 2 ro/di units to to a little test as I think my membrane is bad on both.

I am getting the same tds reading with my hand held tds meter on both the drain line and waste line

And this is after swapping around filters.

Would that be a sign that my membrane is bad?

 

[DLHDesign]

How long did you run the water through the new filter before you measured it?

 

[riche]

How long did you run the water through the new filter before you measured it?

10 -15 min

on the waste water it is coming out cloudy but the good water is coming out clear

 

[DLHDesign]

Hm. My understanding is that they should only take ~5min to flush out.

What is the TDS level you are reading?

 

[AZDesertRat]

What are the Tap TDS, RO only TDS, RO/DI TDS if you have DI and waste TDS? What is your water pressure, water temperature and your exact measured waste ratio?

 

[riche]

What are the Tap TDS, RO only TDS, RO/DI TDS if you have DI and waste TDS? What is your water pressure, water temperature and your exact measured waste ratio?

I will test all that and post it. Do I disconnect the di and run it to test just ro? And what do u mean exactly measured waste ratio? I have a needle valve to adjust it so I am not sure how to measure it

 

[AZDesertRat]

Yes you can disconnect the DI to test the RO TDS.
Use a measuring cup and a clock to measure the waste ratio. First measure the waste for exactly one minute and write the amount in m/L or ounces down. The do the exact same one minute for the treated flow. You should have about 4x waste as treated or a 4:1 waste ratio.

 

[cromag27]

Example:
Tap tds 300
Ro tds 20

300 - 20 = 280
280 / 300 = .93
Membrane rejection rate is 93%

But yes, you do want to make sure your ratio and pressure are correct. what rodi units do you have?

 

[riche]

my tap tds is 164, my ro/di is 114

Temp is 70, pressure is 50 psi

One of the ro/di units I have is a aqua fx barracuda and the other is a unit that has the different style membranes where there are the 3 smaller tubes on top and then 3 canisters on the bottom

 

[AZDesertRat]

Your RO membrane is shot. If the tap TDS is 164 you shouldn't be seeing more than 3-6 TDS in the RO only water and final RO/DI should be 0.

 

[riche]

Your RO membrane is shot. If the tap TDS is 164 you shouldn't be seeing more than 3-6 TDS in the RO only water and final RO/DI should be 0.

Thanks for the quick answers and help