Distilled Water vs RO/DI Water???

[TygGer]

I checked the TDS of Walmart's distilled water and the reading was 0. I then proceeded to check my tap water, 172. If the distilled water reading was 0, how or why is RO/DI water better?

Any how, I just received my RO/DI unit and have many questions... but that's for another thread.

 

[jackdp]

Reverse osmosis/deionized water and distilled are in a nutshell the same thing. Its just 2 different methods of producing pure, mineral free water. A steam distillation apparatus is used to produce "pure" water, there is probably a filtering step in commercially distilled water somewhere. Reverse osmosis water is created by forcing water through a semi-permeable membrane that traps most foreign bodies, the deionizing step forces the water through a charged resin that removes any left over chemicals that RO doesn't catch. Most commercially sold RO water is also subject to physical filtration and activated carbon filtration. For aquarium purposes I would say that both are equally pure, the only catch with distilled is the the piping used during the distillation. Some worry that copper pipes used during the process could produce water with too high of a copper content that could harm inverts.

 

[kidafius]

I think that distilled water will have less trace elements in it than RO/DI. Distilled will also have less desolved oxygen, so you might want to aerate it well if you plan on using it.

 

[claysey]

Kidafius,

How do you go about aerating the distilled water? I use a large commercial distiller for the water used in the tank at my office. Things seem to be ok, but any way I can improve them will always help.

Thanks,
Claysey