R/O vs. distilled water

[Randy Holmes-Farley]

If RO is preferable to distilled water, why do entire countries use distilled water instead of RO?

Someone else has no idea what an ion is.

What can't be trusted is RO water, not distilled water. Your fish store or food store is not obligated by law to change filters and perform other RO maintenance. That's why RO water, particularly from commercial sources, has a wide range of results. I'll gladly wager some money on buying RO water from several fish stores and comparing it to distilled water.

There is only one technique to make distilled water: by heating and condensing it. The only pollutants that can be found in distilled water are those having a lower vapour temperature than water, which are irrelevant to reefing.

RO is clearly more feasible for a small reef or a house owner, but that implies you maintain it and change all of the filters. That is something that the LFS or grocery shop is not required to do. Distilled water has a minimal base quality level determined by physics, and while RO water may potentially remove low vapor point contaminants better under ideal conditions, I don't trust supermarket and LFS stores.

What are you referring to that "entire countries" use distilled water instead of RO water? Used for what?

It is not correct to claim that "The only pollutants that can be found in distilled water are those having a lower vapor temperature than water, which are irrelevant to reefing."

Depending on what the condensed water touches, it can dissolve metal ions into it from metal pipes, and various chemicals from plastic pipes. Copper cooling coils would be a considerable concern. Don't know if they are still used in any parts of the world or not.

These contaminants may not typically rise to a level to be of any concern, but the absolute statement that it cannot happen is incorrect.

 

[Randy Holmes-Farley]

Here's a paper from 2013 where they analyze the chemicals in commercially distilled water in Kuwait and detect copper:

Chemical analysis of distilled water: a case study

(2013). Chemical analysis of distilled water: a case study. Desalination and Water Treatment: Vol. 51, No. 7-9, pp. 1936-1940.

www.tandfonline.com

"This paper is highly concerned with analytical chemical results which are obtained at Doha West Power Station in Kuwait and summarizes the various chemical techniques that carried out at laboratory to emphasize the quality of distilled water through distillation process of the station such as; pH, specific conductivity, iron, copper, silica, total hardness, and chloride during operation."


An example of D4A distillate readings
pH 6.87
conductivity 1.1 uS/cm
Fe 2.4 ppb
Cu 3.4 ppb
SiO2 5.6 ppb
Cl– 0.113 ppm

 

[landlubber]

If RO is preferable to distilled water, why do entire countries use distilled water instead of RO?

Someone else has no idea what an ion is.

What can't be trusted is RO water, not distilled water. Your fish store or food store is not obligated by law to change filters and perform other RO maintenance. That's why RO water, particularly from commercial sources, has a wide range of results. I'll gladly wager some money on buying RO water from several fish stores and comparing it to distilled water.

There is only one technique to make distilled water: by heating and condensing it. The only pollutants that can be found in distilled water are those having a lower vapour temperature than water, which are irrelevant to reefing.

RO is clearly more feasible for a small reef or a house owner, but that implies you maintain it and change all of the filters. That is something that the LFS or grocery shop is not required to do. Distilled water has a minimal base quality level determined by physics, and while RO water may potentially remove low vapor point contaminants better under ideal conditions, I don't trust supermarket and LFS stores.

Good

...great?

 

[HawkeyeDJ]

Good topic.
I'm not crazy about producing RODI water due to the waste. Some systems are worse than others.

I'm thinking of building my own distillery, using reef-safe materials. My area is in a drought and I suspect distilled will be more efficient and less wasteful, particularly if it is solar powered. Lots of sunshine in my area to exploit. I don't need hundreds of gallons produced weekly as my DT is only 24g.

Now, my question is this: What would be the expected outcome if I were to filter my homemade distilled water through a DI resin? Can I expect pure water with little or no waste, or am I missing something?