Sorry guys, I guess I should have explained it. Just wondering what people are using for make up water and water for water changes. 2 is have you gone from say Tap to RO or RO/DI from RO or RO/DI to Tap. I have just noticed some people have, not just here, have gone from RO/DI to just RO or staight back to Tap Water. Now some say they maybe lucky and have not noticed much or any difference going back to Tap some have said they have noticed an improvement going back to Tap or dropping the DI and in doing so have quite the savings in just dropping the DI portion and even more when dropping RO totally when you add in the Waste water. Now I know DI does some funky stuff to the water. It pretty much creates dead water as it strips it and even strips much of the O2 from the water and for some reason it is hard to replace the O2 levels. Example, an article I read quite some time ago on a Fresh Water enthusiast, who fell in love with Discus to the point he wanted to breed them and not just any. He wanted to get them from a Special German Breeder, so he set up a rack of tanks in his Basement and spared no expense and upon receiving his purchase of close to $10,000.00 dollars in rare and hard to find Discus they all went straight to the surface, he lost the enter purchase. He was upset and accused the supplier of poor shipping and after discussing what his preparation was he was told NEVER EVER USE 100% RO/DI a max of 50/50 should be used as it creates dead water and should only be used for Laboratory use, he was told his fish died from lack of O2 and when he tested water for O2 levels where extremely low.
Apparently O2 is not absorb into DI water as CO2 is absorb much easier and faster so it becomes very hard and lengthy time before O2 levels come back to acceptable levels.
SO something to think about. I use a 5 stage dual DI but I have be debating about dropping the DI or RO/DI totally.