RO/DI question

Smite · Dec 21, 2014

I've got my system all set and have made 60 gallons of water so far. My question is how fast should my DI be changing color? The bottom 1/3rd of mine has turned orange/copper.

My TDS reads 25 in and zero out. When I back flush the unit it reads about 170. I'm going to pick up a handheld TDS to test my tap and see what I'm dealing with.

It's the brs plus 150.

New to this just wondering if that's about right for DI depletion.

Adrock · Dec 21, 2014

I would use the regular di not the color changing I feel it last way longer , that's about normal for color changing di . we sell the loose di for 11 bucks. I would recommend since you have a tds meter to get the regular di saves you money and helps your dollar work hard for you . if you want you can bring in a sample of your tap water we can test for free and would be glad to help out !

Adrock · Dec 21, 2014

also the color change on the di is a estimate you will probably have to change once a month or so where the reg di might last 2 to 3 month possibly.

ep3n3wp · Dec 21, 2014

if your water district uses chloramines it will take a toll on your Membrane as well as your di.... if your city uses/adds chloramines you can replace one of the carbon filters with a more powerful carbon block that also reduces chloramines. or to beef up your unit buy a sinlge clear filter canister and add an additional carbon block.

i have a handheld tds meter if you wanna swing by with a sample

pciscott · Dec 21, 2014

When you first turn unit on you will have what is called TDS creep and the 25 number is normal, but after about 5 gallons produced that number should be under 10 depending on your incoming water. Do a test on how much water made verses waste to determine if your unit is working proper. You will need to read up on BRS site to see what it is supposed to be for that unit. Also wonder what rejection rate is on BRS membranes? Take your incoming tds and divide that by percentage and that will give you what number you should be getting coming out of membrane.

The new Spectrapure 99% membranes do work as advertised I have incoming of 300 and have 2 to 3 coming out of membrane before DI which extends the life of your DI by a ton. These I highly recommend to anyone changing membranes.

If your tds does not drop you need to check that membranes are seated and flush them out as in my opinion 25 is very very high going into your di.

There is one other thing to check we did not talk about and that is incoming water pressure. For your unit to work proper you need at least 60 psi of water pressure or the membranes will not run efficiently, this is why they sell booster pumps and if you have low water pressure this could give you problems.

You have my number if you need any extra help trying to figure out why tds is so high coming out of membranes.

Adrock · Dec 21, 2014

pciscott said:

When you first turn unit on you will have what is called TDS creep and the 25 number is normal, but after about 5 gallons produced that number should be under 10 depending on your incoming water. Do a test on how much water made verses waste to determine if your unit is working proper. You will need to read up on BRS site to see what it is supposed to be for that unit. Also wonder what rejection rate is on BRS membranes? Take your incoming tds and divide that by percentage and that will give you what number you should be getting coming out of membrane.

The new Spectrapure 99% membranes do work as advertised I have incoming of 300 and have 2 to 3 coming out of membrane before DI which extends the life of your DI by a ton. These I highly recommend to anyone changing membranes.

If your tds does not drop you need to check that membranes are seated and flush them out as in my opinion 25 is very very high going into your di.

There is one other thing to check we did not talk about and that is incoming water pressure. For your unit to work proper you need at least 60 psi of water pressure or the membranes will not run efficiently, this is why they sell booster pumps and if you have low water pressure this could give you problems.

You have my number if you need any extra help trying to figure out why tds is so high coming out of membranes.

very good info and all may pertain to your situation +1 [MENTION=3580]pciscott[/MENTION]

Justkeepswimming · Dec 21, 2014

My di changed instantly as well. I have been using the system for a couple months and still producing zero tds out. I think you are ok...

Adrock · Dec 21, 2014

Like I said the color changing di doesn't last as long , I feel if you have a tds meter the color changing di is not needed

Buckeye Hydro · Jan 18, 2015

Smite said:

Do you mean your RO water is 25 ppm? That's awfully high, if so. What is the TDS of your tap water?

Russ

Buckeye Hydro · Jan 18, 2015

The presence of the color-change feature really doesn't say anything about the capacity of the DI resin.

Russ

Buckeye Hydro · Jan 18, 2015

ep3n3wp said:

With proper prefiltration the presence of chloramines in the feedwater won't bother the membrane.

RO membranes have a very high tolerance for chloramine - but, free chlorine is often present when there is chloramine in the water, and its the free chlorine, if not treated with proper prefilters, that will attack the membrane.

Russ

Buckeye Hydro · Jan 18, 2015

pciscott said:

BRS uses Filmtec membranes for the most part. They are spec'ed at 50 PSI rather than 60 psi.

Smite · Jan 21, 2015

Buckeye Hydro said:

Hey Russ. I picked up a second TDS meter for the incoming water of my RODI. I rechecked my numbers tonight after it ran for an hour.

PSI is 63
Tap is 440 ppm
After the first 2 stages it drops to 385-390 ppm
After the last 2 membranes its down to 17 ppm.
Now coming out of the DI its about 2 so I'm gonna change that out here soon.

I've ran about 100 gallons so far on the system. BRS states the membranes remove 98%. So I should be getting around 9 ppm out of the last to membranes, right?

I haven't ran a waste water test yet to see if that % is correct yet.

Buckeye Hydro · Jan 22, 2015

With the membrane feed at 390, and your RO at 17, you're at a 96% rejection rate. Not horrible, but higher would be better. Because your system has two membranes plumbed in series (waste from the first feeding the second, the feed water to the second membrane will be higher than 390 - I'd expect something around 470, maybe less depending on some other measurements. You'd have lower RO water TDS if you plumbed them in parallel, or used a flow restrictor that provided adequate concentrate (waste water).

Do we have other issues at play here that would consume your DI resin? Chloramine? CO2? Short-cycling?

Russ

qchau · Jan 22, 2015

Smite,

I have almost the exact same parameters as you except my psi is around 90. I tried almost every possible issue. For mine at least, I think my RO membrane doesn't reject as high as advertised. For my next one I will try the spectrepure 99% and see if that does the trick.

Buckeye Hydro · Jan 22, 2015

Don't forget this Sponsor has the MAXR Membranes with guaranteed ultra high rejection.

Russ

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