Calgary water and RO; what's your TDS after the RO?
 

If you have an RO unit, and you measure your TDS, what typically is your TDS reading after RO membrane (but before the DI stage)?

I know incoming TDS is usually around 400 or so for me. But I was expecting my RO readings to be more in the 5-15 range after my RO, but I usually get readings more like 60-80.

I've replaced my membrane (and all the prefilters of course), but I still get readings like that. After the DI the readings are 0 so I think the TDS meter is OK.

Maybe something in my configuration is causing membranes to fail prematurely? Or can a RO unit be functioning properly and still yield water with a TDS in the 60 to 80 range?

Mine is 0-5 Tony. Something sounds haywire there. Mind you my tap water is around 175ppm. Rejection rate should be 95-99% so you are still way high. The DI won't last long at that rate.

You got that right. 3 weeks on and almost 1/3 done.

Thanks for the info.

I'm pretty sure something's wrong. The fact that I'm on my 3rd membrane in a year that exhibits this means I must have something wrong in my configuration. The only thing I can think of, off the bat, is the fact my RO/DI feeds a number of float valves (1 for each tank). So the pressure in the discharge line is always high (thus shutting off via the solenoid shut off kit). So it's always on for a short burst followed by a long period of off, following the evaporation rate.

The only thing I can think of to change that is to fill a bucket first, then shut off the inlet water. Let the bucket feed the float valves over the course of a day, then refill the bucket in one go (once a day kind of thing).

How do you have your top off? Float switches or float valves?

Mine's not connected to the RO unit at all. Still mostly Barry Bucket around here.... :redface: :lol:

Tony

After my RO a reading of 2. I had a bad membrane and had similar results to what you have going on. Luckily I changed it and things have been running smooth. So you must have something wrong for sure. So you'll have to fix that and I don't think it is related to your float valve set up. I believe it is best for your RO to operate a few times every day, the more the better for it. Is that not what you have happening? I believe the worst thing for RO/DI is long periods of no flow like a day or two.

For info sake I have my RO/DI plumbed into a 5 Gal. pale on a float. In the pale are my two top off pumps. One pump is controlled by a Tsunami see link, it supplies my predator tank.
http://www.mops.ca/cgi-bin/SoftCart....html?E+scstore

It works fine and after three years has not failed (knocking on wood now). It did not have the exact control I was looking for on my reef and went the Tunze top off system on my reef. I love that little toy, pricey yes but does a great job. I'd guess it turns on dozens of times over a 24 hour period keeping the flow through RO/DI going on and off.

Also plumbed out of the 5gal I have a line that flows down to a 33gal rubbermaid to store water change water. There is regular float in that container. And then... from that container I pump manually into other rubermaids to mix salt in.
The end sorry that was so long.

Dave

Aiiee, now I don't know what to think. I thought maybe the constant on/off/on/off/on/off of my setup what was may be killing the membranes.

Anyone consider themselves an RO savant that could come over and help me trouble shoot my setup? The thing is I've been having my RO setup this way for years and only this last year have seemingly had a problem with things.

My water pressure is way lower in my new house than it was at the old house. The first thing I did was T into my water supply before my pressure regulator (I don't know why my house has a pressure regulator so I don't really want to remove, defeat or even adjust its settings too much). Before the regulator the pressure is about 76psi so I assume that's enough to comfortably run the RO.

I'm not sure what else I should be looking at.

Ahhh the joys of no RO. :biggrin:

Is it a new RO/DI or did it work fine at the old house? Assuming it's a older unit...kind of an obvious question but did you change anything on the unit when you moved?

It's a new-to-me unit. Basically the shell and then the innards are all I completely new (membrane, prefilters and some of the fittings).

The one before, as far as I know, it worked fine at the old house. Course I didn't always have a TDS meter though, so my perceptions may be off a bit.

Nothing was changed in the old unit in the move; and it seems to me it was after a year that I really started noticing things going aksew.

Bob, I remember when you told me that only fools use halides over their tanks, and that you would never ever use those. :razz: Thanks for the helpful post though :lol: At least you get one more post count now.

Yes, but you got four to my one. :mad: