Is all RO/DI water @ 0 TDS equal

[CSS Reef]

A question I have always wondered. With water being the single most important part of our reef tanks are all 0 TDS water equal?

Throughout the entire country different areas use different sources of tap water through RO/DI filters to make 0 TDs water for topoff and production of saltwater for water changes etc...... Is there a possible difference that 0 TDS water from San Diego is still different from 0 TDS water in Massachusetss, Florida, New mexico, Germany, Italy etc.........Do we start with a level playing field when it comes to water? Are there areas where the best equipment and husbandry still yield unsuccessful reef tanks because of water quality. OR Areas where the water is so good purity wise that after being ran through RO/DI a reefer can achieve better results much easier??

What could be present in water after registering 0 TDS that could be different from location to location becuase of treatment methods, pollution etc.......?????

[boxfishpooalot]

your questing is entirely dependent on a piece of test equipment called a tds meter. Its accuracy and precision. So you cannot conclude anything until you conclude your test equipment is accurate.

If you are certain it is, then 0tds means exactly that. zero.

[CSS Reef]

I use a TDS meter and get 0 TDS.

So you saying that water from any place in the country/world that tests 0 TDS is indeed exactly the same? If so great but wanted to confirm this. Thanks for your reply.

[CSS Reef]

Actually I think I found my answer......

http://reefkeeping.com/issues/2004-04/rhf/feature/index.php

[AZDesertRat]

No.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=898154

[boxfishpooalot]

the thread posted by azdesertrat is exactly what I am talking about.

A cheapo tds meter will not measure what your looking for. 18.2 ohms is pure water.

[MattAndKim]

There absolutely is a difference between different sources of tap water. Even if you run them through RO and DI. Organic contaminants present in the feedwater may not be removed by your purification and can end up in your tank. IDK that this could have any significant effect, but they are sure to be there. Google tapwater and pharmaceutical or organic contaminant to learn more.

An indication of 0 TDS only means your indication device is below its minimum range. The water does not really have a TDS content of 0.
With a high-accuracy resistance bridge("kind of like a TDS meter"), if you place the conductivity cell in a beaker of fresh DI, you can actually watch the conductivity rise due to carbon dioxide absorption from the air. If your TDS meter reads 0, it cannot detect low-level contamination.

boxfishpooalot:
I think you mean 18.2 million ohms. ;)

Fresh DI output from both mixed and stratified beds I use at work are consistently ~2Mohm. Not familiar with the commercial budget-oriented units in use in aquaria.

[mr pink floyd]

i dont think hes asking specifically about the TDS meters reading. i think hes asking if its homogeneous... if pure water is pure water.

and if thats what your asking then yes. this is all theoretical though.

[CSS Reef]

I think what I was really asking quite simply is since contaminents, pesticides etc.. that dont have an ionic charge dont get filtered out by the DI even though your TDS meter reads zero...........

Does this mean that some areas with reefkeepers that have high non ionic contaminents are out of luck no matter how good they are? Specifically I was talking about keeping SPS.

Only as an example: Its easier to keep SPS in Houston but in Baton Rouge its very dificult to get the same results with the same equipment, husbandry techiniques just different sources of tap run through RO/DI. etc.........