RO and a UV light

[Wanabe1972]

I'm not sure where to post this but you RO guys should have the answers. I will be plumbing my RO this week and was wondering if I should plumb my UV light before the RO or after the membrane. It seems to me that UVing the concentrate only would make more sense but I'm not sure. Thanks Jeff

[wiam]

Put uv before RO. Light will not penetrate concentrate as well.

[markct]

I have a 10gpm water treatment uv light that I use on my concentrate out stream. I originaly wanted to use it on the inlet side but the seals don't hold under suction, since its made to work under pressure in a domestic water system. So I figure what the heck and put it on the outlet side, I was pleasantly surprised how much difference it made, much clearer sap in the storage tank of concentrate, and hardly any slime on the tanks. I know they say it doesn't penetrate as well on concentrate but I figure it cant be too bad, I mean on the inlet it would have about 3gpm flow thru it, on the concentrate its only about 1gpm so it has a good bit more time exposed to the uv.