Distilled water and RODI equal????

[MCooper]

Okay,
So I wanna check if RODI can be used as distilled in equipment (autoclave) as I was going to install one at work?
Anyone know?

 

[MaiReef]

I use RODI in all the distilled water applications, but I never heard a technical answer

 

[BiggieJohn]

RO/DI would be MORE pure the distilled. Distilled water can in theory still contain some VOC's and impurities. It is nearly impossible to control the exact boiling/condensation point to make sure you are getting ONLY H2O and nothing else. RO membranes remove 95%-99% of contaminants leaving only a few very small mineral ions that the DI resin will remove. In a properly functioning RO/DI system with proper prefilters, you should get very close to absolute 0 TDS

 

[PatW]

I agree with the above. I have heard that distillation has the tendency of having certain ions coming through in the water vapor. RODI uses a two part system that removes things pretty thoroughly. The RO membrane should block any macro molecules and most of the ions. The DI resin should clean up the remaining ions leaving water that is pretty pure.

The main advantage is you can have you own RODI system. I know what the TDS is coming out of the RO membrane (2) and it is 0 coming out of the DI resin. I would think that a distillation system is not really practical for a hobby application. That means I would have to buy it and I would be totally dependent on trusting the people who ran the distillation unit to do things correctly. I would be betting my reef on it.

 

[AllSignsPointToFish]

In industrial applications, especially for semiconductor applications, deionized water is made in a multi-step process involving carbon filtration, reverse osmosis, and separate anion/cation resin beds. This is similar to hobby-scale systems, only much more complex as the purity of the water required for semiconductor processing is extreme. Pure water should have a resistivity greater than 18 megohm-cm, and most industrial units for high purity applications run in this range. Distilling water cannot remove all of the low boiling, volatile organics. Another method of purification is required to remove these compounds. In short, good quality deionized water should be purer than off-the-shelf distilled water.

 

[djd3mon]

The only other thing I can add is (Correct me if I'm wrong/uneducated) the still in which the water was distilled was more than likely copper since it is the safest and cheapest material. Or it could of been distilled with a stainless steel still. Either way I don't think you would know....unless you build your own still out of stainless and distill it your self.(dont get any funny ideas and try to make some old hooch ) I would not want to take the chance in getting any molecules of copper in my tank....even though I'm pretty sure down the road we will all have it in our tanks eventually. Just my .02

 

[AllSignsPointToFish]

The only other thing I can add is (Correct me if I'm wrong/uneducated) the still in which the water was distilled was more than likely copper since it is the safest and cheapest material. Or it could of been distilled with a stainless steel still. Either way I don't think you would know....unless you build your own still out of stainless and distill it your self.(dont get any funny ideas and try to make some old hooch ) I would not want to take the chance in getting any molecules of copper in my tank....even though I'm pretty sure down the road we will all have it in our tanks eventually. Just my .02

True, but you could always test the DI water with a copper test. Normal seawater contains something like 0.003 mg/L of copper, just for reference.

 

[MCooper]

So it seems the RODI water will be safe for the autoclave machine from what I am reading!

 

[djd3mon]

So it seems the RODI water will be safe for the autoclave machine from what I am reading!

RODI is the only option.

 

[MCooper]

RODI is the only option.

Actually Distilled is what is recommended for the autoclave by all autoclave manufacturers. I just wanted to see if can use RODI for it as well as that is all I use on my tank of course.

 

[Randy Holmes-Farley Verified Community Expert]

Actually Distilled is what is recommended for the autoclave by all autoclave manufacturers. I just wanted to see if can use RODI for it as well as that is all I use on my tank of course.

And as folks noted, you can as long as it is 0 ppm TDS.

 

[BiggieJohn]

And as folks noted, you can as long as it is 0 ppm TDS.

extremely pure water (RO/DI) can actually be a problem if heated to boiling, or above as in a steam autoclave.
There is nothing in the water to provide nucleation sites for the bubbles to start forming and agitate the water.
The water could in theory become superheated and never turn into steam until the water was disturbed somehow then it would instantly flash to steam exploding violently.

 

[AllSignsPointToFish]

extremely pure water (RO/DI) can actually be a problem if heated to boiling, or above as in a steam autoclave.
There is nothing in the water to provide nucleation sites for the bubbles to start forming and agitate the water.
The water could in theory become superheated and never turn into steam until the water was disturbed somehow then it would instantly flash to steam exploding violently.

Use boiling chips?

 

[Randy Holmes-Farley Verified Community Expert]

extremely pure water (RO/DI) can actually be a problem if heated to boiling, or above as in a steam autoclave.
There is nothing in the water to provide nucleation sites for the bubbles to start forming and agitate the water.
The water could in theory become superheated and never turn into steam until the water was disturbed somehow then it would instantly flash to steam exploding violently.

Have you seen that reported to happen? That's no different with good distilled water, and the sides of the container are usually the sites of nucelation of boiling water anyway.

 

[BiggieJohn]

Have you seen that reported to happen? That's no different with good distilled water, and the sides of the container are usually the sites of nucelation of boiling water anyway.

MythBusters covered this once

 

[Randy Holmes-Farley Verified Community Expert]

MythBusters covered this once

I meant an autoclave issue.

 

[djd3mon]

Actually Distilled is what is recommended for the autoclave by all autoclave manufacturers. I just wanted to see if can use RODI for it as well as that is all I use on my tank of course.

Hmm. I just assumed "autoclave" was some kind of reef tank...like red sea 170..lol

 

[Betty1964]

Interestingly enough, using RODI water in my CPAP machine voids the warranty. I can only use distilled. It seems to me that the autoclave would be the same deal.