ro/di help

[hooked]

Hello,

Most remember my massive nitrate problem around 4 months ago. I purchased a ro/di unit and did weekly water changes to get my nitrates down to 12. For the past 5 weeks I have been wondering why my nitrates will not drop lower then that and think I have found the reason. I have at most made 100g with my ro/di and today I tested a fresh batch of water from it and I have nitrates around 8-10 range. I was told the filters would last 6 months maybe longer depending on my usage, well I think 5g a week isn't much at all. I guess I will start by calling the manufacture and asking them. Will a fresh batch of ro/di water show the nitrates like I am getting? Any thoughts on this?

Thanks,

[Doug1]

Contact the mfgr, I would think they should be lower after RO/DI . Have you recently tested source water for nitrates before treating?

[hooked]

Hey Doug,

My source water is testing out right around 12. I will call them on tue. I think the filters should last longer then that.

[UnseenTric]

hooked-
Wow I can't believe that your getting that high of a reading on the RODI effluent. Are you using a Salifert test kit? And if so, Is it at all possible that you are picking up some residual No3 from prior nitrate tests? I had the same problem with my Salifert NH3 test vial, I used it so much in the beginning that its trashed, and always gives wacky readings. It might be worth giving the test another shot in another test vial that is clean....
Not saying I don't believe you but 8 ppm from the effluent on 4 month old filters sounds suspect to me-Especially for 5 gallons a week.
Just thought of on more thing! Do allow the system to flush the first 2 gallons that comes out? I've tested that water TDS, and its no good. If these RODIs sit around stagnant for too long, like 2-3 days, I'd certainly flush a gallon or 2. HTH
FWIW
Pete

[hooked]

I am using a tetra test nitrate kit. I think there test kits could be my problem. I will try to flush 2 gallons out then test. I have a aquatic reef ro/di system.

[tdwyatt]

Originally posted by hooked
I am using a tetra test nitrate kit. I think there test kits could be my problem. I will try to flush 2 gallons out then test. I have a aquatic reef ro/di system.

a quality product, the membranes would not be passing that much nitrate unless they were either allowed to dry out for some time, or if hot water were run through them, or they were exposed to too high a line pressure (like really high...) Flushing the system out or discarding the first several liters would be a good test, but I am suspect of your test kits to start with. Might try testing some distilled water from a reputable distilled water manufacturer (try some usp rated distilled water from a pharmacy, nitrates on USP DISTILLED water are ZERO). Spectrapure makes a kit to flush out the brine side of the ro membranes, but you can probably make one yourself. This extends the life of your membrane as well.

Hope this helps, I'd get in contact with our sponsor from ARS.