RO DI Unit

[stevil]

Originally Posted by Jerthunter
...you said that both 100 gpd and 125 gpd membranes could fit into the housing? If this is so, would it be one of the 100 gpd membranes that operate at lower pressure?
That's what I believe. A couple of clarifications though - the membrane must be of the same style (size & shape). Also there are also 100 GPD (or less) membranes that require higher pressure (more 100+ PSI). And, you should be aware that some of the membranes have a higher rejection rate than others, meaning they will be inherently slower (and require more water)

 

[ezee]

Hey all,
So I got my RODI and installed it. Although I got a couple of leaks thus far that has not been a problem. I am, however, getting less than half a cup an hour, about 6 gal a day as prev mentioned. I am hoping that something can probably be done about it but I am not quite sure what. The only I can thing I can think of is that I did not drill out the feed hole after I pierced it (I am getting seemingly decent flow from that hole though). Or maybe my PSI is low? Not sure. Anyone have any ideas?
Oh, one more thing. In the instructions to this unit it actually says that average usage for the unit is 150 gallons PER MONTH. I am not sure if this is indicative of the capabilities of the unit but it is a little frustrating to think that they are passing off a very slow model personal RODI drinking unit for a 125 gpd RODI system.
E

 

[bgriff]

GPD becomes a mute point if you have storage capability. I connected my unit to a brand new 45 Gal heavy duty trash can with a float switch. I placed a power head in the bottom to keep the water moving and I now have enough to maintain a 55, 39, 20 and 10 gal tanks in my home. (Ok, I have to coordinate mass water changes, but the point is I have about 40 gallons available and it replenishes on its own.

 

[stevil]

Originally Posted by ezee
...I am, however, getting less than half a cup an hour, about 6 gal a day as prev mentioned. ... The only I can thing I can think of is that I did not drill out the feed hole after I pierced it (I am getting seemingly decent flow from that hole though). Or maybe my PSI is low?
Oh, one more thing. In the instructions to this unit it actually says that average usage for the unit is 150 gallons PER MONTH. I am not sure if this is indicative of the capabilities of the unit but it is a little frustrating to think that they are passing off a very slow model personal RODI drinking unit for a 125 gpd RODI system.
E
Try drilling out the feeder hole (assuming you used the needle valve) - also make sure the valve is all the way open.
Also, try flushing the membrane for a few hours (yes, this will waste a ton of water). You could also periodically flush the membrane and you should see a marginal increase in output, but only temporarily.
Unfortunately though, I don't think you're going to see much increase, at least not the orders of magnitude required to get 125 GPD.
My theory is that a RO membrane that does less GPD, but is able to operate at lower pressures would increase output substantially. If you search on google for "low pressure ro membrane" there are several vendors that provide them, and you can see tables & charts that show GPD, Max PSI and rejection rate (this is somtimes called different things, the higher the percentage the better).
I bet we'd all get 100-125 gallons per day if the water pressure was around 200PSI, however, most homes are regulated at 45-55 PSI.