My Vertex PuraTek RO/DI unit is leaking, and I'm in need of new O-rings. I think they are the standard RO/DI canisters just like everyone else has and the BRS canisters. Does anyone know where to get them locally? Would Home Depot or Lowes have them?
Also, before, I didn't use Silicone Grease, but I just got a tube from BRS that came in. I'm sure it's safe to use on o-rings, and makes the seal better, but I just wanted to double check if there is anything dangerous that could leak into the water? Also, do you just apply a thin coat, or thick coat? Thanks.
I always order mine from www.allorings.com
I just needed a replacement for mine. Emailed the filterguys and he sent me one for free.
Amazon sells o-rings now. Pretty cheap and free shipping if you are a prime member.
You just need a small amount of silicone grease.
I have been using it for years with no problems.
Does anyone know the size of the o-ring?
I bought the GE o-rings for their RO units at Home Depot and they were a tad to large.
Gresham, what size o-rings do you order? Thanks.
Oh man, that's a huge question.... I use a ton... from 1/4" to 10". I don't just use them lie you should... sometimes I simply use them to block light from escaping with no need to be airtight.
I'll measure my RO o-rings and let you know.
I'd shoot an email to Vertex... last time I contacted a company for a part, they sent it to me free 
Also, before, I didn't use Silicone Grease, but I just got a tube from BRS that came in. I'm sure it's safe to use on o-rings, and makes the seal better, but I just wanted to double check if there is anything dangerous that could leak into the water? Also, do you just apply a thin coat, or thick coat? Thanks.
You might look for a irrigation and/or pump supply house in your area. They usually carry a WIDE selection of O rings. Take one you have with you and they can match it.
Companies that sell bearings also usually have O rings.
Of course if you are in the middle of SF you might have a drive to find such a place. Out here in the sticks it's not a problem. 
I found Lowe's to have a better selection of o-rings. The one near me in Sunnyvale has a ton while the HD has very few.