TDS, low PSI, etc etc...

[WhiskeyCoffee]

So at my last place I was on city water and now I've moved to a house on a well. Let's figure some things out...

Old house: 80 PSI, 88 TDS from tap, 0 TDS after RODI, waste was 200+ TDS
New house: 40 PSI, 110 TDS from tap, 3 TDS after RODI, waste is 112 TDS

So, a couple questions. Why would my TDS increase from 0 to 3? Could it be the high levels of iron and manganese in my tap? Also, why is the waste TDS more or less the same as the tap TDS? That part has me baffled...

 

[Cory]

Co2 in well water will kill deion resin. Lucky you, ive got well and get 600-900ppm and 6-20ppm after ro.
Whats the tds after the ro membrane?

 

[Ty Hamatake]

I hear PSI has a lot to do with how effective the RO membrane is. More stuff getting through the RO might result in more getting through the DI?

 

[Maacc]

Grab a booster pump, wells typically have variable psi and 40 psi causes a lower rejection rate and much below that can start to cause scaling of the ro membrane. Also change your di resin if you have stuff getting through it's exhausted, also consider a dual di stage.

 

[Randy Holmes-Farley Verified Community Expert]

Regardless of the RO membrane function, one would expect the DI to get water to 0 ppm TDS. Might it just need to be changed?

 

[WhiskeyCoffee]

Regardless of the RO membrane function, one would expect the DI to get water to 0 ppm TDS. Might it just need to be changed?

Could be. Do you know why the waste water wouldn't have a higher TDS than the source water?

 

[Ty Hamatake]

Could be. Do you know why the waste water wouldn't have a higher TDS than the source water?

My guess is that new water has different level of different contaminants. If I understand RO/DI filtering correctly, each stage is for different types (sizes?) of contaminants. Whatever it is (I think silicates and ammonia?) that makes it through the RO membrane may just be in higher concentration in the well water than it was from the city. Maybe another reason your DI resin is letting more stuff through...

 

[Randy Holmes-Farley Verified Community Expert]

Could be. Do you know why the waste water wouldn't have a higher TDS than the source water?

But it does, doesn't it? How much higher depends on the waste water ratio to source water.

That said, I wouldn't put a whole lot of focus on the specific numbers since they are not likely to be super accurate in a cheapo monitoring device, and are not going to be temperature corrected.

 

[WhiskeyCoffee]

Co2 in well water will kill deion resin. Lucky you, ive got well and get 600-900ppm and 6-20ppm after ro.
Whats the tds after the ro membrane?

Can I use my Red Sea test kits to test my tap water for pH and KH to determine CO2?