RO/DI vs DISTILLED

[motopsycho]

Is there any difference in the water quality between Distilled and RO/DI ?

The reason I'm asking is I had someone come to my house last night trying to sell me a Distiller for my house. Sounded like a great idea, never have to change filters and less waste water. IMO - the downsides were the cost and only 5GPD.

Poor guy seemed very confused and had never heard of someone using close to pure water (RO) for fish and not for my family. We cook with tap water. He also was even more confused when he tested my RO water (Have had the same filters on my Aquasafe since December, making about 30G a week plus top off water) and the TDS read lower then his distilled. My RO was reading 0.5 and his distilled was 1.5

Thanks
Chris

[Monti]

Distilled should have no solids at all unless his distilation equipment was dirty. The water evaporates and is condensed on a cold surface then runs into a receiver flask. There is absorbs CO2 and props in pH to about 5.5. It can be the purest form of water made because the distilation process removes both the dissolved solids and the dissolved organics (as long as the bp is higher than 100C.

RO/DI will remove most of the dissolved solids and may even get some of the dissolved organics, but not all of them.

Does it matter for a reef? I don't think so, but other may have another opinion.

[motopsycho]

Thanks,

Anyone else want to offer their 2 cents?

[Bioterrorist]

I remember reading something about copper condensing tubes, but I can't remember all of it. I also remember something about distilled being ionicly unbalanced and stressful to the fish.

[Chrismo]

Most or all distilled water is made in Metal canisters or drums. So even though you get pure water with the evaporative process, the metal storage container contaminats it. (Invertabrates are much more sensitive to metals than we are).

So it could be that the 1.5 TDS is all copper say... and that would kill your corals.

Chris

[motopsycho]

Good point Chris, I never even thought about the storage container. I guess I will hold on to the $3000 and stay with my $100 Aquasafe unit :bwink: