I don't know, if I was more of a RO savant sort of person I'd help but I'm not. Is it a brand name filter set up? Maybe post a pick of the set up and some might notice a flaw in the configuration. If that doesn't work sell it to some one from Edmonton, get a new one and be done with it!

One other thing, you say "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. " Is that because you got a TDS meter? Could the thing be screwy from the get go?

For what it's worth I have one of these units and it's great because it supplies quality drinking water as well. The difference in taste is amazing.
http://airwaterice.com/product/1DUALHR

Dave

Bob Bob Bob...I thought you believed in constructive posts. :razz: We folk who don't take our tanks down every couple months have to have other options you know... :lol:

Tony, I did get a bad membrane from AquaSafe, proved it by substituting with someone elses. You might try that.

One bad membrane sure but three? Something is wrong.

Dave

I've switched the configuration for now to only fill my water barrell and just feed the float valves off that; will see if this makes a difference. It usually takes about overnight to fill that thing and it holds, I think, 40g, so a fill should last me about a week.

If I flush the membrane then the TDS on the output falls down to 15 which to me seems a more acceptable level (although I still wish it were a little better, but hey it's better than 60).

As far as configuration goes I'm not really sure how you can screw up with these things? Water goes in, water comes out in two places, and one of those streams is more better than the other. :lol: You need a flow restrictor that matches your membrane capacity and you put that on the waste line (otherwise a flush kit doesn't do anything). Am I overlooking anything here? And then I guess the only thing is if you want to get real tricky you can put a flush bypass valve on your waste line, and the solenoid shutoff which feeds off the output line and impacts back to the input line.

I guess when I say "three membranes" I should qualify that the first was, of course, several years old so maybe it doesn't count. So really I'm looking at being on my second replacement membrane and I'm wondering what's up. I would have upgraded the membrane anyhow though since the old one was 35gpd and I wanted to go to 100gpd (although it's not 100gpd at the pressure it's run on). I am using, as far as I know, the appropriate sized flow restrictor.

Anyhow thanks for the thoughts ... will have to scratch the noggin a bit more on this but for now I'll see if the reservoir changeout has an effect.

Is it possible that the membrane housing is the problem. Perhaps the membrane is not fitting properly and is allowing some unfiltered water to leakpast and mix with the RO water.

From what I’ve read and been told the less you use a RO/DI the less efficient the unit becomes. Unless you have an automatic back flow that cycles every so often and then it does not matter.

Good luck with it, post your results. I can tell Bob he’s lurking because he wants a RO/DI!

Dave

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Yes, us fools with our RO units are just staying mainstream Bob. The fact is though, Calgary water not only has higher PO4 and chlorine, but the heavy metals are what will inhibit your tanks' success over time.

In all honesty though, our tap water is not that bad. Not nearly as bad as others. I should invest in an RO/DI , and I know I should have one by now. Just can't find the funds to order a brand new one online. A used one on the other hand.... I would be fine with that.

So my 55g drum or however big it is finally emptied over the weekend. Gave it a rinse and turned on the RO/DI to refill. I first flushed the membrane, after about 30 seconds the TDS in the post-RO (pre-DI) step came down from about 80 tds to about 15 tds. For the remainder of the fill the tds on this step hovered around 13-15. That seems not so bad, although it's not the 2 or 0-5 that Monza and Emilyb report. (Anyone else measure the TDS between the RO membrane but before the DI? What are the numbers you get?) Post-DI the tds is a solid zero but the resin is now almost halfway consumed.

So I think what's happened in my case is the constant cycling of the unit due to the top off for multiple tanks led to premature failure of the membrane. 15 tds isn't too bad but I think I'll budget for replacing the membrane again and take it as a lesson learned.

There is an interesting idea for combating "TDS creep" in the latest reefkeeping.com featured aquarium where the guy has his float valve inside a chamber inside the reservor that doesn't kick off the float valve until the reservoir is completely empty, thus allowing the RO to kick on only to fill the reservoir from empty (instead of the constant on-off to match the evaporation rate). http://www.reefkeeping.com/issues/20...totm/index.php

Although given how long my drum lasted before refilling I think I can live with manually turning on and off my RO from now on.

Hey Tony.

For what it's worth, I used to get reading no higher than 0 to 4 after my membrane.

My Di cartridges were lasting about 8 month's to 1 year.