Super deionized water bad?

yacobito

Member
Ok, I work in micro and nano electromechanical systems (I build little tiny devices) and we have a massive deionized water system. The DI water is very very very pure, has to be for all of our processess, and I was wondering if anyone thinks it would be bad or ok to use it in water changes for my 30G SWF tank. Remember when I say very pure I mean SUPER pure. Thanks so much :thinking:
 

taz_12777

Member
I do believe it should work fine for you. Most R/O units also use the DI as well. You can buy DI units to use from home. As you said the water is very pure but when you add your salt to it it gives you a very good SW mix. I have a small unit I use and the only problem I have is some plants are not doing so well . I have to look into it alittle more to see what I need to add to the water. lol
 

yacobito

Member
Hey thanks for the replys. I do have access to the water tretmenat area. I think I will take your advice and use the water from the RO unit before the DI system as top off water and maybe used the finished DI water for water changes (adding salt). As a matter of fact or CEO will only drink coffee made with the RO water. He claims it tastes better!

I have tried it and can't really taste a difference, but when you are CEO you get what you want I guess.
I will make sure and test and watch the PH very closely. :happy:
 

vlondi

Member
You must have been told incorrectly. Aside from "just created" water, the is no such thing as pure H2O. Water by its very nature seperates into hydroxide and hydronium at various points in its existance. A pure, water-like substance is pretty much always composed of H2O, OH, and H3O. The OH is basic and the H3O is acidic, but in "pure" water these two neutralize each other (in a sense).
"Pure" water exposed to air should have a pH of around 6.3 because of carbonic acid; any water below 5.6 is pretty much considered an acid.
 

yacobito

Member
Vlondi is right. You will always have OH, and H3O. When you deionize water you get ride of both foreign ions, such as
Na(+1) and Cl(-1), and any EXCESS OH and H3O. I think the DI water system we have takes water to 20 MOhms or maybe higher. Thats some prettty clean water!
 

doboy

Member
Yacobito,
I don't know if this helps you, but I used "ultra pure" water for about 10 years in FW tanks. My dad worked for a purified water company for 30 years, so not only did I get the benefit of a lifelong education in water (I emaphasise the LONG), I also has access to all the water I could want from the plant. I filled up my tanks with it, I did all my water changes with it, and never had any problems because of it.
The systems they used were the most advanced (and costly) in the bottled water business. For that reason, the company eventually could not compete, and was purchased. The system was: a UV sterilizer, charcoal, 3 stage RO (the third stage is the TFC membrane), and DI. If forget the actual numbers, but it calssified as AR (analytical reagent) grade water. In fact, the machines were equipped to add minerals back to it for drinking,
There are a couple things you can do with this pure of a water (like what you are talking about) to demonstrate what pure water can do. You said your boss only drinks coffee using that water. If you look inside the coffee machine there will be no mineral deposits. Because the water has almost nothing in it, it actually acts as a solvent.
IMO, if you can get it, use it. BUT, since there is nothing of value for your critters in it, you are going to have to make sure you put in the appropriate nutrients/minerals etc. You have to do that anyway, but this way, you know you are starting from zero.
 

sly

Active Member
I only wish I had access to that kind of water. FYI, there's no way that pure water has a pH of 4, even if the test says it is. I'll have to look up the literature to remember the exact science, but it has something to do with ion concentration. DI water has no buffering capacity like normal water does. It is these buffers that seperate into + and - ions in regular water. The pH meter measures the concentration of these ions and determines the pH of the water. In DI water, because there is no buffering, there are no ions to measure and so you can get some very extreme readings with a pH pen. This does not mean that the water is really that acidic. It isn't. The pH of pure water has been and always will be at 7. It's the testing method that is at fault.
 
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