DI water

[Toggil]

What's the difference between DI water and RO water? I was just at my LFS checking out saltwater stuff and they have a thing that deionizes water, it looks like it's just a tube with some stuff in it that the water goes through. Can this be used in place of RO water for a tank?
Also the store sells fiji rock for $6.99 for what they call premium and $8.99 for like super premium, can't remember what exactly it was labeled as. Are these good prices? I figure it's probably better to buy locally than have shipped from some site on the internet but I don't want to get ripped off.
Thanks.

 

[saltwater84]

To be honest, I think that that is way too much for live rock. I have seen live rock as low as 1.99 per lb on some websites and 3.99 per lbs on some lps. I rather buy it off the net and paid the shipping cost, it still cheaper than buying 6.99 per lbs.

 

[BlackGhost]

DI just deionizes the water but does not take out all the impurities. Most good RO machines come with DI units attached. If your looking to save money by not having to buy RO water from the LFS there are some cheap ones out their that are $100.00 that will take 99.9% of everything out of the water. Making the water safer for fish.

I just bought mine at Dr Foster and smith and its working pretty good