New RODI unit, few questions

[nunofs]

With my Typhoon V, I have about 250 incoming TDS, and 0-1 RO, 0 RODI. (I don't go through DI resin very quickly at all.

Wow, I never get that kind of efficiency with my unit, that's 99.6%... I also have tap water around 250ppm, but my RO TDS is around 20... anything in particular that you did to your unit to perform like that?

Nuno

 

[NateHanson]

I haven't done anything. I got the unit used, and operated it for about 6 months with low single digits tds RO, and 0 tds RODI, and changed the sediment and carbon cartridges recently. Now getting 0 and 0 on most readings. I didn't change the DI because only the bottom inch of the color-change cartridge had turned brown. The rest appears unused.

The only thing I can think of that might be beneficial is that we use our RO water all the time for drinking water (have a tap at the kitchen sink), so the unit probably cycles a lot more often than many units. Perhaps the constant use is helpful? Thats just a guess.

Maybe it's just a good unit. Anyone with a Typhoon V getting similar results?

 

[nunofs]

The only thing I can think of that might be beneficial is that we use our RO water all the time for drinking water (have a tap at the kitchen sink), so the unit probably cycles a lot more often than many units. Perhaps the constant use is helpful? Thats just a guess.

I also use RO for drinking water (via a 3 gallon pressurized tank underneath the sink)... I tend to fill two gallon jugs at a time, and then we use the water from those jugs to avoid cycling the unit frequently (which I read is not a good idea, but your usage and TDS values prove that wrong).

Nuno

 

[NateHanson]

Ok, here are some updated figures that may sound a bit less miraculous. I may have been remembering the TDS from before I installed a whole house filter on my water service line (just a single stage sediment cartridge). Tonight I'm reading 105 at the tap. 2 at the RO. 0 at the RODI.

So I'm getting 98% efficiency. Still not bad, eh?

Nate

 

[MikeG]

I would think that the TDS of the source water would dictate the TDS of the RO/DI water. As long as the unit is around 97-100% removal I think things are working well. I have a TDS reading at the tap of 450ppm and after RO/DI it is 7ppm.

 

[this is me]

1:4 is a good ratio.
I tried RO water a couple times but never with DI. I read that the DI can cause trouble to your stomach or something like that

 

[NateHanson]

I would think that the TDS of the source water would dictate the TDS of the RO/DI water. As long as the unit is around 97-100% removal I think things are working well. I have a TDS reading at the tap of 450ppm and after RO/DI it is 7ppm.

I think that's true for the RO stage, and RO efficiency should be in the range you mention, but the DI resin should remove any remaining dissolved solids, and I believe the result should really be zero, or very close to zero after the RODI. I'd say 7 indicates some service is due. Perhaps new DI resin.

 

[MikeG]

I think that's true for the RO stage, and RO efficiency should be in the range you mention, but the DI resin should remove any remaining dissolved solids, and I believe the result should really be zero, or very close to zero after the RODI. I'd say 7 indicates some service is due. Perhaps new DI resin.

I'm not sure what I could do for service as this unit is new. I have only produced about 60 gallons of RO/DI water and these are the readings I have been getting from the start. Could be due to the fact that the water source is a cold water line, so the temperature is not ideal. Any other thoughts? It is a 60 gpd 4 stage Kent unit that I am using.

 

[NateHanson]

I believe cold water will only slow the water production by the membrane, not make it higher TDS, I believe.
The first diagnostic would be to test your RO product water. It's efficiency should be around 95%, I'd say. So under 20 for your water. Then I'd expect your DI to take it to something closer to zero from there.

What size and type are the 2 stages in your unit before the RO?

 

[MikeG]

As far as size do you mean pore size ie. micron?
It consists of a CF1M 1 micron sediment filter, a CFCE solid block carbon pre filter and a SILICAMAX Hi Removal dual stage deionization cartridge

http://www.marinedepot.com/md_viewItem.asp?idproduct=KM1433

 

[nunofs]

I was also going to say that you'll probably need to replace the DI resin, but you're saying that you always got these values since the beginning... that's strange.

The thing with DI resin is that it becomes exhausted much more quickly when the TDS of your RO water is higher, so the worse water you have the more frequently you'll need to replace the DI resin.

I would still try replacing the resin, it can't hurt.

The other alternative that I'm thinking about is that your membrane may be punctured and letting a lot of dissolved solids go through... some are being caught by the DI resin but not all, leading to the 7ppm reading.

Or, it may be just a miscalibrated TDS meter...

Nuno

 

[NateHanson]

Test you're RO water. That'll go a long way in diagnosing the problem.

 

[MikeG]

I still don't think it is the DI resin, one because it is basically brand new and two it is a color changing resin and there has been no change in color. Now you have me wondering if the TDS meeter needs to be recalibrated. Do people calibrate their meters when they get them or rely on the manufacturers calibration. This TDS meeter is calibrated at 90 ppm I believe so I don't know if that would have an effect on the desired readings. I'll test the RO water tonight to see if that will help resolve the issue, thanks for the advice.

 

[Greg Hiller]

>From my reading of RO/DI its not good to drink....After many gallons of drinking this stuff it strips your body of the minerals it needs.<

Ah...the myth never dies. RO/DI is fine to drink. Your body will make up for the minerals from the food you eat. You are correct it doesn't taste that good...it doesn't taste like anything.