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Twinfallz
02/04/2017, 06:20 PM
Hi Russ;
I'm wondering about the main purpose of a carbon filter in an RODI unit.

How important is the removal of organics by adsorption when the conversion of chlorine to chlorides is done by electron exchange, and this is not necessarily affected when adsorption capacity is reached?

The conversion of chlorine is very important for the sake of the RO membrane (of certain types).

But wouldn't the RO membrane, & if necessary, the DI units take care of the organics in the case where adsorption capacity has been reached?

If this is the case, then measuring free, or total chlorine at the outlet would be an accurate measure of when the carbon needs replacing.

thanks for any feedback

regards
steve

Buckeye Hydro
02/05/2017, 07:35 AM
The main purpose of carbon prefiltration in units used in this hobby is treatment of chlorine and or chloramine. Organics are rarely an issue on municipal water

Twinfallz
02/05/2017, 12:20 PM
The main purpose of carbon prefiltration in units used in this hobby is treatment of chlorine and or chloramine. Organics are rarely an issue on municipal water

How about oxidisers other than chlorine that can damage RO membranes. Like iron & silica? Can they occur in significant concentrations in municipal water. What would be the best way to deal with that?

Greg 45
02/05/2017, 12:37 PM
Buckeye Hydro you were using the term organic's in the thread above. For year's I myself have never trusted the final tds out of a ro/di. This isn't about your systems but the ones I have used personally. Zero reading might have a meaning to people that build units. Here is why I don't Agree . My tap water has over 120 ppm of phosphates and the unit I was using will still pass p04 even at zero. To solve the problem I run 3 di cartridges on the unit and one in the 100 gallons of water already made. What causes this. Please advise.

Buckeye Hydro
02/06/2017, 03:15 PM
How about oxidisers other than chlorine that can damage RO membranes. Like iron & silica? Can they occur in significant concentrations in municipal water. What would be the best way to deal with that?

Iron and silica are not "oxidizers." Both can foul an RO membrane.

Buckeye Hydro
02/06/2017, 03:25 PM
Buckeye Hydro you were using the term organic's in the thread above. For year's I myself have never trusted the final tds out of a ro/di. This isn't about your systems but the ones I have used personally. Zero reading might have a meaning to people that build units. Here is why I don't Agree . My tap water has over 120 ppm of phosphates and the unit I was using will still pass p04 even at zero. To solve the problem I run 3 di cartridges on the unit and one in the 100 gallons of water already made. What causes this. Please advise.

120 ppm of phosphates? Are you sure about that number?

Greg 45
02/06/2017, 03:45 PM
120 ppm of phosphates? Are you sure about that number?

yes sir that's out of the tap / tested multiple time / also called the water department about it. I can grow algae all day in a cup of water .
This is tested with a Milwaukee mi412 .

Buckeye Hydro
02/07/2017, 07:08 AM
That meter has a MAX detection limit of 2.5 mg/L (ppm)

Buckeye Hydro
02/09/2017, 07:36 AM
I don't think your test result on that phosphate is accurate. Does your meter report results as ppb (ug/L)?

Greg 45
02/09/2017, 05:02 PM
I forgot the dot trying to up load pictures wont go through at 1.31 today . Big mistake on my part .

Buckeye Hydro
02/09/2017, 10:00 PM
That makes much more sense now!