RO/DI--people who have it can you help me?

Myka · #1 03-19-2008, 12:46 AM

Check the tds of the the water that comes out of the RO, but BEFORE the DI. You'll have to take it apart to do that. Just disconnect the line between the RO and the DI, and collect that water to test it. How many gpd is your RO?

sharuq1 · #2 03-19-2008, 12:53 AM

TDS there is 18. The unit is supposed to be 100gpd. Also TDS before "polishing" filter (after DI) is same as what is coming out when polishing filter is hooked up, so guess it isn't that.

littlesilvermax · #3 03-19-2008, 01:44 AM

Quote:

Originally Posted by sharuq1

TDS there is 18. The unit is supposed to be 100gpd. Also TDS before "polishing" filter (after DI) is same as what is coming out when polishing filter is hooked up, so guess it isn't that.

If your post RO tds is 18 ppm, then you have one of three things:

1) very high tds water (like 600 or so) and it exhausts your DI quickly
2) a bad membrane (FWIW the 75 gpd, I like the Filmtec, seem to consistently outperform the 100 gpd ones)
3) very low pressure to the unit

How to solve the problems:

1) just have to live with it (BTW someone around here has awesome deals on DI resin)
2) get a new mambrane, and by the sounds of how much you are using stick with the 75 gpd ones
3) get a booster pump

FWIW even if your pressure is good, a booster pump wil up efficiency, that is why I bought one.

Myka · #4 03-19-2008, 02:13 AM

The membranes have different efficiency rates.

Filmtec 50 gpd = 98% rejection rate
Filmtec 75 gpd = 98%
Filmtec 100 gpd = 90%
BFS 150 gpd = 98%

If your tap water is 225 ppm, and you're getting 18 ppm out of the RO, then your efficiency is about 92%. If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. This way you should get about 4-5 ppm out of the RO, and your DI resin will last much, much longer. This is probably your cheapest solution.

mark · #5 03-19-2008, 02:40 AM

I'm running single digit TDS, not zero, but don't think it's the end of the world (this is considering the cups of salt mix I add, the Dow Flake, the Mag Flake and some people do keep reefs with tapwater).

midgetwaiter · #6 03-19-2008, 05:27 AM

Quote:

Originally Posted by Myka

The membranes have different efficiency rates.

Filmtec 50 gpd = 98% rejection rate
Filmtec 75 gpd = 98%
Filmtec 100 gpd = 90%
BFS 150 gpd = 98%

If your tap water is 225 ppm, and you're getting 18 ppm out of the RO, then your efficiency is about 92%. If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. This way you should get about 4-5 ppm out of the RO, and your DI resin will last much, much longer. This is probably your cheapest solution.

Myka is absolutely correct. Your unit is working correctly but because of the lower rejection rate of the membrane you are using up DI resin very quickly. This is why the Aquasafe units are cheaper but also not very effective with Alberta water.

The flow restrictor on the Aquasafe isn't a capillary type like used in most systems, it's built into the flush valve so if you do decide to get a new membrane you will also have to replace the restrictor, it costs only a couple dollars.

You will have to decide when you want to swap your DI, it's not a clear cut choice. 6ppm probably isn't a big deal but it depends what that 6ppm is. Test the water for phosphate at least and if you start to see that come through then it's time to replace the DI. Spring is here so you can expect to see some more phosphate then usual.

Slick Fork · #7 03-19-2008, 05:06 PM

I think you will defineatly have to buy a booster pump, those aquasafe units seem to be real fussy about pressure. DO NOT buy one from one of these outfits in red deer. check out www.purelyh20.com the booster pump will run you about $100 (as opposed to $300 here in red deer), a new membrane in the 75 gpd flavour will cost you about $30-$40 with the flow restrictor and flush kit (highly recommended). Make sure you insist on USPS for shipping otherwise UPS will whap you with a big brokerage fee. If you need DI, littlesilvermax is the guy to grab it from!!

Also, if your turning the source water on and off all the time, that may be hard on your membrane as well. Your aquasafe should've come with a pressure switch that turns the water on and off automatically without letting the membrane dry out.

sharuq1 · #8 03-20-2008, 02:40 AM

Thanks for all the great advice everyone.

Where could I buy a new regulator and membrane for this unit? It is going to be some time before I can actually buy anything at all (sooo broke), but when I can at least I will know where to go.

banditpowdercoat · #9 03-19-2008, 03:21 AM

My source is 500-700PPM, and I routinely get 10-11PPM after DI

sharuq1 · #10 03-19-2008, 03:57 AM

Quote:

If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient.

Flow restrictor? What exactly is that? Is it the valve on the input or the metal valve on the output? Or is it something else? Are you saying I will need a whole new RO membrane?