Distilled Water

[1shibainu]

I am a bit new to reef keeping and was wondering whether it is a good idea to use distilled water.  I have heard that distilled water tends to be on the acidic side (especially when left exposed to air).  I assume that one would need to re-add minerals back into the water in order to use it for the reef, correct?

[Sahin]

I thought distilled water was practically same as RO or DI water?  

 

Assuming its the same thing, it should be about neutral, and the pH is brought to appropriate levels by the salt mixture.

 

Hey I could be wrong, I have only been into Reef keeping myself for 8 weeks and had a tank for only 4 weeks.

 

But I think I am right.  Lets see what the others have to say.

[Leonard]

Distillation is an entirely different process from reverse osmosis.  Distillation is the process of purification whereby a solution is repeatedlysteamed and condensed to extract pure water from the heavier solids in the solution.  In laymen's terms, H2O- which is lighter -  is evaporated, condensed, and collected while the heavier solids are left behind.  Theoritically, distilled water is pure water with a neutral pH.  When left in air, any water (not just distilled) can become slightly acidic when it absorbs atmopshereic CO2.

 

R/O runs water through a semi-permeable membrane, "sifting" out larger molecules to form purified water.  Deionizatoin uses charged ions to strip the minerals in water to purify it (often called softening the water since it removes primarily carbonates and earth metals).

 

Yes, true distilled water is perfectly suitable for reef tanks.  In fact, most distilled water is more pure then RO.  However, make sure the water you buy is pure distilled, and not drinking water.  Water companies usually add minerals to drinking water to improve tastes.

 

You may wish to reconstitute/remineralize purified water with some commercially available buffers, but I find no use in doing so.  I just use C-balance or B-ionic, which is sufficient to make up necessary elements in proper ionic proportions of natural seawater.

 

(Edited by Leonard at 7:28 pm on June 18, 2002)

[1shibainu]

Thanks for the info guys....I just wanted to be sure that distilled water was safe to use for a reef tank.

[snafuforyou]

keep in mind some distilled water is processed with copper pipes. look into NSW - its cheaper than distilled and no mixing

[flaunt]

hmmm... i was going to say that you might want to contact the company and make sure that their water doesn't flow through any pipes or containers that are made of copper during the distillation process, but if they did that it would seem to defeat the purpose of distilling the water wouldn't it?  even so, i would not assume that it didn't touch copper pipes.

[Leonard]

IIRC, Cu levels of distilled water for scientific applications registered under 1 part per BILLION.  Even lesser distilleries should not impart enough Cu to make the water toxic.

[Satchmo]

Also, some water labeled as distilled are actually processed by RO.  The water I'm using for example... small print on the bottom of the jug... "Processed by carbon filtration and reverse osmosis."  Although it's labeled distilled.