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broncofish
10/01/2008, 06:13 PM
I recently purchased a new membrane, DI canister and sediment filters. I changed all the filters and added a 10 micron carbon block of my own. The DI resin has been nearly half exhausted in less than 100 gallons of water. I'm about 99 percent sure everything is hooked up right. Any thoughts? Thanks.

Khandurian
10/02/2008, 11:48 AM
What is the TDS coming into the first prefilter?

What is the TDS coming out of the RO before going into the DI chamber?

broncofish
10/08/2008, 09:18 AM
I just ordered a TDS from you today. I'll let you know as soon as I hook it up. Thanks, and sorry for the late reply.

Khandurian
10/08/2008, 01:34 PM
You ordered a TDS from them. I just help answer questions in here sometimes. Although, it will be interesting to see what your dealing with.

Remember, test the incoming (out of the faucet) first.
Then After the RO
Then After the DI

broncofish
10/14/2008, 12:18 PM
Ok, tester came in a few minutes ago and I hooked it up. After the RO its 9 and after the DI its 0. Is this where its supposed to be? The resin I bought has produced less than 100 gallons and is 4/5 gone. Any idea?

jdieck
10/14/2008, 01:59 PM
Are there any chances you are getting high dissolved CO2 in the inlet water?
YOu can test the alkalinity and PH of the tap water and use the table to calculate the content of CO2. Normal amounts are in the 2 to 5 ppm, if more than 10 that may speed up the exaustion of the resin.
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

broncofish
10/14/2008, 05:58 PM
Its water at our school..... so who knows. I do have a digital pH tester I can use, but I have had resin before with no problems. Or maybe I didnt notice.... both are equal posibilities. Too bad they dont make dialysis RO tubing.

jdieck
10/14/2008, 06:04 PM
<a href=showthread.php?s=&postid=13544671#post13544671 target=_blank>Originally posted</a> by broncofish
Ok, tester came in a few minutes ago and I hooked it up. After the RO its 9 and after the DI its 0. Is this where its supposed to be? The resin I bought has produced less than 100 gallons and is 4/5 gone. Any idea?
What type of resin did you used? What is the TDS PPM of the tap water (input to the system)?

broncofish
10/14/2008, 07:00 PM
Resin I assume was a mixed blend. It was a cartridge from this vendor. I'll check the input(tap) ppm, but what does it matter if the TDS after the membrane is 9. I checked later in the day and I think it was at 4 or 5.

jdieck
10/14/2008, 07:35 PM
<a href=showthread.php?s=&postid=13547245#post13547245 target=_blank>Originally posted</a> by broncofish
Resin I assume was a mixed blend. It was a cartridge from this vendor. I'll check the input(tap) ppm, but what does it matter if the TDS after the membrane is 9. I checked later in the day and I think it was at 4 or 5.
Which vendor, can you link?
If you are using a high rejection TF membrane, having 9 ppm at the membrane ouput it may mean that your input PPM is in the order of 600 to 650 ppm which seems very high for a school water system. If your actual TDS in the tap is say 250 that means the rejection of the membrane is only 96% which may indicate a deteriorated membrane is high rejection is being used.
BTW all Filmtec membranes of 75 gpd or less are high rejection.

broncofish
10/15/2008, 03:59 AM
I got it from air water and ice. Thats why I put it in this forum to begin with, I thought someone from here would chime in. I'll check the input(tap) TDS and see what I come up with. What is a good post membrane TDS I should be looking for?

broncofish
10/15/2008, 08:21 AM
Alright, tap water is 400 ppm. pH of tap water is 7. I just made another 55 gals of water last night and it appears the resin is exhausted. I'll just keep an eye on the output TDS to see how long it takes to climb.

jdieck
10/15/2008, 09:46 AM
<a href=showthread.php?s=&postid=13550177#post13550177 target=_blank>Originally posted</a> by broncofish
Alright, tap water is 400 ppm. pH of tap water is 7. I just made another 55 gals of water last night and it appears the resin is exhausted. I'll just keep an eye on the output TDS to see how long it takes to climb.
At a tap of 400 and RO output of 9 your membrane rejection is:
% rejection = (400-9)*100/400 = 97.8% A bit lower than the expected 98.5% but still within the range of the TDS meter accuracy and the membrane performance so we know the membrane rejection is OK.

At 400 ppm and PH of 7 I can say that the alkalinity might be high, this could mean that the water is laden with CO2 but to really know we need the alkalinity of the inlet water. Can ou test your inlet water's alkalinity? You can use the kit you have, is most probably also good for fresh water.

Khandurian
10/18/2008, 10:05 AM
It's also possible that you may have just gotten a bad batch of resin.

Since it "appears" (my eyes plays tricks on me sometimes) make another 55 gallons. If the TDS stays at zero, it may be that your eyes are playing tricks on you as well.

If the TDS starts to creep up, send an email to airwaterice from their website. Tell them all the numbers that you have just told us. You will get a much faster response (usually withing a few hours on a week day!) and see what they can do for ya.

Good Luck!

jdieck
10/18/2008, 11:35 AM
400 tap and 9 out of membrane that is 87.8 rejection which is OK.
With 400 ppm and 7 PH chances are there is high CO2 in the tap. Can you test the tap alkalinity? This way we may know how much CO2 the tap has.

Warboc
03/16/2009, 01:57 PM
I am having the same issues with my unit. If it is a high CO2 issue, then how is this resolved? All my tubing is clear. I have noticed the inlet from water source to rodi unit has turned to a yellowish brown tint. Does this indicate anything about the water quality/contents?

My tds from tap is 172, tds after RO is 5, tds after di is 0.

I can make around 100 gallons of water before I have to change out the DI resin. It's a Typhoon III unit and I have called and emailed Air Water ice for assistance. However, we've not made heads or tails out of it. They've even replaced my filters and ro membrane for free.

The unit ran fine for a year until we moved into a new hours. That's when the fast depletion started. Obviously something with the water, just don't know what.