What's a reasonable TDS reading for SR?

[woodnaquanut]

I just put a new RODI in service. It's got one of those cool input/output TDS meters.

After running for the hour BRS recommends, it reads the incoming water at 2ppm. Can I trust it?

For those of you in SR that measure your tap water, what is your TDS reading?

Thanks,
John

 

[lokii_37]

When you say incoming do you mean coming into the DI?

Incoming to my RO is about 125 I think, it's been awhile since I checked it. Into the DI I get 1 and out of the DI I get 0

 

[woodnaquanut]

Thanks for the info, Nick.

I mean source water. 'From the tap'.

As soon as I wrote the first post, I remembered to look up SR water tests.:thumbsup:

The most recient test report is anywhere between 130 and 360ppm. I'll change the battery(s) and see if that helps.

 

[thysrof]

Sounds right to me. Im guessing you have the same little blue faced TDS meter that measures in and out.

 

[woodnaquanut]

Yep, little 'blue faced dude'!

Not very useful if it tells me the city water is 2ppm TDS. If the water was really that good the RODI would not really be needed.

 

[Grant W]

Down here in Petaluma my incoming is around 160 and outgoing is Zero.

 

[gdm42001]

149 here in North West Santa Rosa

 

[thysrof]

John,

Their pretty cheap. If not working I'd buy a new one

 

[AMAYEU]

Fwiw 110-120 sf city

 

[woodnaquanut]

Thanks everybody. Kind of what I expected. I'm surprised the SF numbers are so high. I thought that Hetch Hetchy stuff was ultra pure.

 

[Reef Bass]

110-120 is pretty "clean". Some municipalities run tds upwards of 800. Some wells can be 1500+.

 

[AMAYEU]

Thanks everybody. Kind of what I expected. I'm surprised the SF numbers are so high. I thought that Hetch Hetchy stuff was ultra pure.

Hetchy ranges from 20-200. Some ppl say they consistently get 20-30. I found interesting that numbers are high during the day and low at night.

 

[Reef Bass]

My speculation is that with water demand being lower at night there's less flow, less turbulence, lower tds. That water goes through miles and miles of pipe.

 

[AMAYEU]

My speculation is that with water demand being lower at night there's less flow, less turbulence, lower tds. That water goes through miles and miles of pipe.

Hmm so run your water at night to increase the longevity of your ro/di...

 

[woodnaquanut]

OK, I need Grant to come over, bring a 2x4, and SLAP ME UPSIDE THE HEAD!

I replaced the battery, got same results. As a last resort I read the instructions! Turns out the TDS meter is installed on the output of the RO and output of the DI. It should be low (RO doing it's job) on the IN side. It should be zero on the OUT - DI doing it's job.

I feel so foolish! Been a computer guy for 20 yrs. You would think I knew what RTFM means!!

A mind is a terrible thing to loose!!

 

[lokii_37]

Well at least you know it's working.

 

[Grant W]

OK, I need Grant to come over, bring a 2x4, and SLAP ME UPSIDE THE HEAD!

I replaced the battery, got same results. As a last resort I read the instructions! Turns out the TDS meter is installed on the output of the RO and output of the DI. It should be low (RO doing it's job) on the IN side. It should be zero on the OUT - DI doing it's job.

I feel so foolish! Been a computer guy for 20 yrs. You would think I knew what RTFM means!!

A mind is a terrible thing to loose!!

YES PLease, John. Yes inbound or source water for the first reading and after all filters for the outbound. You got it now. Wait a minute........you're trying to trick me into coming up there so you can put me to work.

 

[lokii_37]

I don't test me source water. I check going into the DI, after RO, and out of the DI. If you don't check it coming out of the RO how do you know when to change your RO?

 

[woodnaquanut]

Wait a minute........you're trying to trick me into coming up there so you can put me to work.

Oh No. My motive has been discovered!!! :eek2:

 

[woodnaquanut]

I don't test me source water. I check going into the DI, after RO, and out of the DI. If you don't check it coming out of the RO how do you know when to change your RO?

I agree with you. After thinking it over it is interesting to know what the source water is. It doesn't really change anything and I'll just trust the water agency reports. It would have an effect on how long the RO would last.

It does matter what's coming out of the RO. As it goes up (membrane clogging?) DI will be used faster. At some point it's worth changing the RO membrane.