RO/DI set up & efficiency..

[dazed]

So I have a few questions about the new ro/di unit that I just set up it is the spectrapure maxcap 5 stage unit; I completed the rinse up procedure per the instructions and then measured the concentrate to purified water ratio; from the yellow wasteline I collected 700ml in 1 minute and from the blue ro/di line I collected 250ml in 1 minute. If I'm doing the math correctly this gives me a ratio of 2.8 to 1?

From what I understand I need to adjust the flow restrictor length from the chart I figure 1.5" is what I need to cut; So do I cut 1.5" off or do I need to cut the flow restrictor to a total length of 1.5"??

I also checked the ro membrane rejection rate the unit has 2 inline tds meters:
(1st tds meter)
TDS in=250
TDS after ro membrane=4
(2nd tds meter)
TDS in=0
TDS out=0

250-4=246 (246/250=.984) (.984 x 100=98.4% rejection rate) if I did the math correctly.

62psi operating pressure, temp was 69°

I also have the com-100-meter handheld; I made 4 gallons of ro/di and got a reading of 0.1ppm

I know the waste ratio has to be adjusted but other than that does everything look okay??
This is my first time using one of these and want to make sure that I'm doing it correctly.

[dazed]

anyone??

[AZDesertRat]

Other than trimming the capillary flow restrictor to adjust the waste ratio it looks like you are right on track. My MaxCap has been consistently averaging 99.23% rejection rate for almost a year now, and thats with a tap water TDS that often exceeds 800. It pays to get the best!

[dazed]

So the 0.1ppm reading from the com-100 on the 4 gallons of ro/di that i made is ok?
i will cut off the 1.5" and see what it does to the waste/ro ratio.

[AZDesertRat]

Thats pretty low, you are talking about one tenth of one part per million. I find my COM-100 bounces between 0.1 and 0.0. As long as its that low you are way below the detection and accuracy level of any other meter you could buy. You might also occasionally test the same points your dual inlines are testing to check their accuracy. You will come to depend on the COM-100 I guarantee.
Make sure you triple rinse the COM-100 in DI water after each use and before putting it away each and every time to keep it clean and accurate. I rinse both the meter and the glass I test in or the cap if I use that and put them away clean for the next use. I amazing how much a dirty glass or meter will throw a reading off.

[DarG]

I've been getting 98.75% out of my Filter Guys unit. It pays to save $150 - $200. :D

[dazed]

So last night I tested the 4 gallons of ro/di that i made a couple of days ago and got a reading of 9ppm?? The water is stored in a 5 gallon bucket with a lid; so what would cause the number to rise?? I thought i could make up the water and store it for future needs??

[d4a2n0k]

<a href=showthread.php?s=&postid=10326491#post10326491 target=_blank>Originally posted</a> by dazed
So last night I tested the 4 gallons of ro/di that i made a couple of days ago and got a reading of 9ppm?? The water is stored in a 5 gallon bucket with a lid; so what would cause the number to rise?? I thought i could make up the water and store it for future needs??

The water needs to be tested in a clean glass, no plastics. All plastics will leach something.

As for storage, those are the breaks with plastic. The longer you store the water, the more it leaches. Many people store water in buckets, garbage cans and bins with no problems. I never let the water sit for more than few days before I do a water change but a lot of people store the water for a lot longer with no problems.

As soon as the water touches anything, its no longer pure. All you can do is start with the best water possible and deal with it.

[AZDesertRat]

It can absorb CO2, attract dust or just about anything. The bucket might have been used to mix salwater previously or do a water change or even new buckets can still have mold release agents on them. You will always see a little bit of something no matter how clean you maintain things. Nothing to really worry about.

[DarG]

<a href=showthread.php?s=&postid=10326491#post10326491 target=_blank>Originally posted</a> by dazed
So last night I tested the 4 gallons of ro/di that i made a couple of days ago and got a reading of 9ppm?? The water is stored in a 5 gallon bucket with a lid; so what would cause the number to rise?? I thought i could make up the water and store it for future needs??

I use a plastic 35 gallon rubbermaid garbage can. It's old, like 8 years or so. I get 0 TDS testing in the bucket as well as right off the DI. Maybe cause it's old and done leaching whatver it leaches? I dont know.

[dazed]

Thanks to everyone for the responses; the reason i was concerned is because this weekend i plan to set up a 55g drum for storing the ro/di water and i guess i was just shocked to see the leaching starting to occur; guess i will just let it be and see if the new storage container leaches anything back into the water.