Help with Phosphates for RODI

[hsd94]

Hello Guys, questions -
My phosphate levels are reading -

Before DI is 2.5mgl to 3 (RO membrane)

Finish water is 1 to 1.5 mgl of phosphate (After DI)

4+ Tap water



Is this level of phosphate okay?

Is the RODI system working fine?

Should the RODI be taking out all phosphate?



DOW Filmtec membrane & Resintech Color changing DI resin. 1 micron sediment, 1 micron Carbon, 5 micron Carbon. Dual DI canisters.



Recently changed all filters, flushed membrane, and tightly packed DI.



TDS reading - 0 ppm



Cleaned filter sock, did water change, etc..



Thank you in advance for any support/help

 

[blaxsun]

I never worry about phosphates in my RODI. If the TDS is 1 or 0 (preferably 0) I'm a happy camper.

 

[nereefpat]

Have your measured a freshly mixed batch of saltwater using the RODI? You might do that, as the PO4 kit would be for saltwater.

 

[Randy Holmes-Farley Verified Community Expert]

I don't see how you can have 1-1.5 mg/L (ppm) of phosphate in water at 0 ppm TDS, nor do i see how you can have 3 mg/L after the RO membrane.

How are you measuring it? Are you certain those units are correct?

I can believe 3 ppm in raw tap water, and 0.05 ppm in 0 ppm TDS water.