RO vs. RO/DI

[gabew]

I have a question regarding RO filtration. I currently have a RO filter set up filtering my tap water but I have seen a lot of RO/DI filters and I was wondering, What does DI stand for? What does the DI part do? Is the DI part necessary for aquariums? and How hard is adding DI if necessary?
Thanks

 

[allsps40]

De-ionization. Having a DI on your RO will take and any remaining tds that the membrane misses. I have been use just a RO unit for 3 years with not problems. I dont even check my tds, just replace the filters.

 

[89Foxbody]

The difference between just RO and RO/DI is like 99% to 99.9%

 

[RealReef7]

honestly i've been using just an ro system for about 3 years and no problem.

 

[Anthonius]

I also just run RO... DI is nice but to me not worth the extra $

 

[RBU1]

Not sure if this is the cause but it sure is a coincident....It seems like my DI resin needs to be changed every few months. Even thought my TDS reading is 0. It seems like I start to get a few small patches of cyano in my tank when the DI needs to be changed. As soon as I change the DI I notice the cyano go away. Like I said could just be a coincidence but it happens every time.......

 

[snorvich]

Not sure if this is the cause but it sure is a coincident....It seems like my DI resin needs to be changed every few months. Even thought my TDS reading is 0. It seems like I start to get a few small patches of cyano in my tank when the DI needs to be changed. As soon as I change the DI I notice the cyano go away. Like I said could just be a coincidence but it happens every time.......

A very interesting observation. :idea:

 

[chartwell]

I have been running RO only for two years, the TDS coming out is 0 and I've not had any problems...

 

[Reefahholic]

Glad you asked that question, I was wondering the same thing.

There's an RO/DI link on the newbie section, but it sadly no longer works. Or at least it doesn't for my computer.

However, there is a ton of information on this site that is like a gold mine for a newbie like myself.

 

[frankpayne32]

In reverse osmosis filtration water is forced through a selectively permeable membrane filtering out molecules larger than the solvent (water). Deionization is a different filtration process that uses exchange resins to remove minerals from the water. Deionization often catches stuff that the RO unit may not. For example, if your source water is high in silicates your RO system will likely not remove much of it while adding a DI unit will do that job. HTH to clarify.