TDS question

[Sea Turtle]

Do phosphates fall into the catergory of Total Disolved Solids (TDS)? In other words can I still have phosphates passing through my RO/DI unit even though it is saying TDS = zero?

 

[rbursek]

I do believe if you would have Phosphates it would show up as a TDS.

 

[Sea Turtle]

OK. Thanks. I guess I really didn;t have to just go and spend $60 to replace all the filters then. :x

 

[rbursek]

Have you tested your RO/DI water for Phosphates?

 

[Sea Turtle]

Have you tested your RO/DI water for Phosphates?

No I have not. The guy at the LFS did. He said that it was fine. But I have my doubts.

 

[rbursek]

ST,
triing to understand the original question? Is it a curiosty question, or do you have phosphates in your tank water and wondering if it is coming from your RO/DI?

 

[Anonymous]

I don't have the calibration of the phosphates vs. conductivity handy, but most hobby TDS meters are not accurate enough to verify the presence or absent of the phosphate.

Typical NSW phosphate is in the neighborhood of 5ppb, and if the conductivity meter is calibrate to using phosphate as a standard (most use "KCl" or "552" or "NaCl"), can it even be able to detect 500ppb? For anything less than 1ppm, most hobby meter just give you a "0" reading. If a hobby TDS meter can show the presence of phosphate, the level would be so high that you can use it to fertizer your garden

 

[Sea Turtle]

I don't have the calibration of the phosphates vs. conductivity handy, but most hobby TDS meters are not accurate enough to verify the presence or absent of the phosphate.

Typical NSW phosphate is in the neighborhood of 5ppb, and if the conductivity meter is calibrate to using phosphate as a standard (most use "KCl" or "552" or "NaCl"), can it even be able to detect 500ppb? For anything less than 1ppm, most hobby meter just give you a "0" reading. If a hobby TDS meter can show the presence of phosphate, the level would be so high that you can use it to fertizer your garden

That's what I was thinking. Thanks. I should habe my new filters this week sometime. I have the feeling that the tank is going to really improve significantly once I change them out.