Rodi Unit high Tds

helldiver · Mar 12, 2016

I have a value brs rodi unit 150gph 4-stage in tds is 275 out tds is 180,pressure reads 38,I also bought handheld tds Meter to check out, and out reads 185.I have replace membranes and resin and cartridges
I Had already ran about 200 gallons through new cartridge s and membrane per brs support and still can not get the number s down
HOW DO I get tds readings down

cb684 · Mar 12, 2016

With this concentrations in and out I would think the problem is either the membrane that is damaged or part of the water is not passing through the membrane. The concentration after the RO unit and before the DI should be 15 or less (hopefully less). Make sure all the tubing and the membrane are attached correctly. If so you may have a defective membrane.

helldiver · Mar 12, 2016

Do u think a booster pump will resolve or how do u resolve 2 defective membrane s

cb684 · Mar 12, 2016

I don't believe a booster pump will resolve it. If you tried two membranes and had the same problems, I would say that the probability of the tubing to be connected wrong or the membrane to not be tightly attached internally is high.
Did you get the two membranes from BRS and they are the right one for your system? If so I would say it is unlikely (but not impossible) that both were damaged.

TheEngineer · Mar 12, 2016

You're only getting a 35% rejection ratio. That's pretty terrible. Your pressure is pretty low which certainly isn't helping but I don't think that's the major problem here. I agree something seems wrong with the setup. Maybe someone can lend you their RO chamber and you can try theirs.

AZDesertRat · Mar 12, 2016

Is this a single 150 gpd membrane or two 75 gpd membranes?
What is your tap TDS, temperature and pressure at the membrane?
What is the RO only TDS before the DI and the final RO/DI TDS? What is your exact measured waste ratio using a measuring cup and timed for exactly one minute from the waste and treated lines? Are you using softened water or if not do you know your water hardness?

helldiver · Mar 12, 2016

Ok Ty I will do this and let you know

Buckeye Hydro · Mar 16, 2016

I suspect your RO membranes are not properly seated.

Russ

AlexStinson · Mar 16, 2016

With that pressure I would try to use just one RO membrane, I believe the brs comes with 2x 75gpd membranes. I assume only 1 membrane is the issue, and it is letting all the water through.

AZDesertRat · Mar 16, 2016

Take Russ up on his offer! Great guy.

helldiver · Mar 17, 2016

Ty Russ I disconnected everything and ran water only through the membranes,tds went down a little,I read a lot of info and watched BRS video.I really think in need a booster pump,my system is a 150 gph system and Brs stated in video requires at least 40 psi only getting 35 psi

Buckeye Hydro · Mar 17, 2016

Yes - your pressure is too low for a single 75 gpd membrane, let alone two plumbed in series. But that's not the cause of what you're seeing. I suspect either your readings are bad, or your membrane(s) aren't seated. Neither costs anything to address.

Russ

Buckeye Hydro · Mar 17, 2016

......

helldiver · Mar 17, 2016

So where do you start I bought and handheld tds meter thinking my readings was wrong and they was not I noticed when I got pressure up to 40 tds dropped 50 points.

Yasmar01 · Mar 1, 2021

I had the same issue with my RO unit. I had well water with a 400 plus TDS and vey low pressure. All of it was solved when i attached a booster pump.

Yasmar01 · Mar 1, 2021

From the FilmTec technical manual

Saltyreef · Mar 1, 2021

Yasmar01 said:
I had the same issue with my RO unit. I had well water with a 400 plus TDS and vey low pressure. All of it was solved when i attached a booster pump.

Thank you for bumping this 5 year old thread

Yasmar01 · Mar 1, 2021

Lol...just noticed that. It came up in my feed like it was new.

SteveMM62Reef · Mar 1, 2021

BRS Has very good Videos on YouTube, on how to set up an RO/DI System. Includes how to set the Membrane all the way down in the Shell. I have a Six Stage Unit, with an add on 150 GPD, plus booster pump set at 75psig My TDS IS One or Zero. If you guys are on a Well, like I am, make sure you have a strainer on the inlet of your system, to protect it.