RO/DI Question

[BigTruck6o2]

I just got a 110GPD RO+2DI REVERSE OSMOSIS water FILTER from filterdirect about a month or 2 ago. I got it because my last one was so old i decided just to get a new one. My problem is im getting a phosphate reading of like .2 out of it. It should be zero im assuming...any idea why its like this?

 

[Biggen]

First off. Are you using a kit specifically designed to test FW PO4?

Second, is there any kind of polishing filter (carbon filter) in line AFTER the water goes through the DI? If so, this could be your source of PO4.

Third, is the DI resin still good? I know you said the unit is new but I just thought I would ask. If you have access to a TDS meter that will give you an indication on whether the filter is performing properly. Also, some DI resin is meant to change colors when it expires. Good DI resin is brown while exhausted resin turns green.

 

[BigTruck6o2]

1. Not sure...its the Rea Sea..Reef Lab, that leads me to believe its only for saltwater but im not sure.

2. No, elbow comes straight out the DI into the bucket

3. Resin is still be good, You have your colors mixed up for good and bad this is what his site says "When the resin is used up, the green color resin will change to brown color." I might have to get a TDS meter and see what it says

 

[Biggen]

Hmm, those colors are opposite on what my resin looks like. Mine goes from brown (which it is now) to green when exhausted. Wierd...

What is the level of PO4 coming out of your tap? It is possible that it is so high that the filter cannot remove it all.

You might want to also take a sample down to your LFS and have the test it for PO4 to verify your test kit.