Distilled water vs rodi

[doma25]

If it is more convenient and I don't mind spending the money can I just use distilled water for top-offs?

 

[BAD FISH]

I wouldn't recommend it but people do. What are you keeping in the tank

 

[bkstang]

Distilled water from a supermarket is no better and no worse than RODI water. In some cases it may be better if you RO/DI unit is not working properly. I used distilled water to start my 29 g tank and I used it for the next 7 months with corals and fish without any problems.

 

[oh207]

Actually distilled water is worse. It does have a higher TDS count. In fact some distilled water bottles does list the TDS count.

 

[bkstang]

I've never heard about it. Are you sure you are talking about distilled water or spring water? Can you give an example of the brand that list TDS in its distilled water?

 

[oh207]

I don't recalled which brand listed the TDS count for distilled water. I know that the FDA definition for it is 0-10 PPM. So depending on the brand you can be anywhere within that range and still be considered distilled.
I read something Randy-Holmes once post that said the issue to consider with distilled water is the process itself. The distillation process will leave solids behind but the cooling coils used could be copper which could leach into the final product.

 

[homegrowncichlid]

Agree on distilled water and dissolved solids, well actually any dissolved liquid that would have a boiling point near water. The technology depends on how well the distillation process is. Which is evident in the liquor industry, when trying to separate methanol from ethanol. Cheap brands just have more contaminants vs top shelf. Revere osmosis I believe, has the highest purity, but my science is 10 years old. FDA and the and the clean water act may set guidelines on what the maximum allowable limits, of which suppliers would shoot for, but once thy hit the target, they wont try to make it purer, unless there's a conscious image brand .