RO units

[silvershark]

ok i'll say it again! i'm getting my new discus tank very very soon and wanna get an RO unit for it!

whats a good make and would it be ok to get one second hand?
also i gather the water from them has absolutly no o2 dissolved in it so how do i go about pre injecting before use?

 

[Lateral Line]

Since you will be adding the water to a body of existing oxygenated water, O2 is not really a problem. I assume you know that a far bigger problem is the lack of buffering potential and the possibilities of vast pH swings.

I don't think I would ever buy a used RO unit. You have no idea what condition or age the mebranes are. If you can get a quality unit for a steal of a price, and reckon on replacing the membranes maybe.