Why am I burning through DI Resin?
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SPSREEFS
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Icecool,
No absolutely not. Hardness will not destroy the ro membrane. However, do resins will suck up all the hardness right out of the water, exhausting your resin in days. I thought I explained on the first page of this thread. Take your test kits and measure the well water......calcium and kh.....
No absolutely not. Hardness will not destroy the ro membrane. However, do resins will suck up all the hardness right out of the water, exhausting your resin in days. I thought I explained on the first page of this thread. Take your test kits and measure the well water......calcium and kh.....
Randy Holmes-Farley
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Hardness (calcium and magnesium, primarily) are generally equally or even more easily removed from tap water by RO membranes than sodium and chloride (the primary ions most of the time).
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That isn't true.
Calcium (and magnesium) is typically as or more more easily removed by an RO membrane than is sodium (because they are larger hydrated ions so penetrate the RO membrane more slowly), so from that perspective, hardness is not a problem for DI resins and a softener will not help preserve the Di resin.
The reason to use a softener is to protect the membrane from calcium carbonate precipitation onto it, which eventually can clog it.
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No, it is only important if you are getting low flow from a clogged RO membrane. It does not do anything to deplete the DI extra fast.
SPSREEFS
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Sorry guys. Not true. Once I softened my water, my do lasts over 6 months. Before I softened, less then a week. I have a very large system that will do 250 gpd. I service tanks for a living. Our water is extremely hard And polluted. Softening the water solved my problem hands down. Many other wholesalers in the LA area will tell you the exact same thing........
Randy Holmes-Farley
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If they do tell the same thing, the'yd also be wrong on the explanation.
I do not know why you observed what you say, but RO membranes of both types do a better job on calcium and mangesium than on sodium that they are swapped for. You can see that in this sort of rejection data:
http://www.watertreatmentguide.com/Membrane_Rejection.htm
from it:
Rejection Rates
Thin Film Composite Reverse Osmosis Membranes
Calcium 93-99%
Sodium 92-98%
Magnesium 93-98%
Cellulose Triacetate Reverse Osmosis Membranes
Sodium 90-95%
Calcium 92-95%
Magnesium 94-97%
Randy Holmes-Farley
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FWIW, here's a detailed discussion of how hardness causes scale on RO membranes and ultimately destroys the RO membrane:
http://www.watertechonline.com/the-effects-of-hard-water-on-reverse-osmosis-filtration-systems/
http://www.watertechonline.com/the-effects-of-hard-water-on-reverse-osmosis-filtration-systems/
SPSREEFS
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Possibly the gross amount left is enough to wipe out the di cartridge???? Not sure, but I know it works and works well. When my softener tank starts to lose its charge, the water hardens and the di goes by the wayside quickly. I am sure its not only calcium, but other minerals as well. And in all fairness this could be a case of demographics as well. Could just be our water from this area. But he can check rather easily to see if his water is hard........
SPSREEFS
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Randy,
That article proves my point exactly in the headet. Pre treatment of water!!!! Besides carbon filtration(which is in the room unit anyway) water softening is mentioned first! And a simple test will give him a good start....
That article proves my point exactly in the headet. Pre treatment of water!!!! Besides carbon filtration(which is in the room unit anyway) water softening is mentioned first! And a simple test will give him a good start....
Softening is the best thing you can do for your tap water when using a RO system, that is not in question. The OP though only has a tap TDS of 60 to begin with and 2-3 TDS permeate from the RO membrane so softening will have limited value. The issue is low pH and entrained CO2, things a softener will not help to any degree. If the TDS is only 60 we already know the calcium carbonate hardness can't be very high.
You are not talking to inexperienced reefers or water quality experts here. I myself have operated and managed municipal water treatment plants for 40 years and am confident I have much more knowledge of the subject than yourself. I know Randy is even better infored than myself. You are preaching to the choir here.
You might want to look at the tens of thousands of threads and posts both of us have on the subject before making a fool of yourself.
You might want to look at the tens of thousands of threads and posts both of us have on the subject before making a fool of yourself.
SPSREEFS
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Are you saying I'm wrong on different units of tds measurement.??? Or garbage measuring devices??Your overlooking blatant possibilities that should all be factored into his problem.... Sorry I'm not impressed.....
OP
OP
TheEngineer
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I appreciate all of your thoughts in support of my DI resin saving mission 
I'm thinking of devising an experiment to test if CO2 is indeed the culprit we suspect it is. It only takes about 10g of RO to make a noticeable dent in the color change resin. I already have two cartridges so I think I will run two separate setups and see what I get.
Setup 1 is the degassing setup I currently have.
Setup 2 will be a 10g barrel with an air stone in it for 24 hours.
I'll measure how many fractions of inches of DI are depleted after the 10 gallons is produced and see if there is a noticeable difference between the two methods.
I'm thinking of devising an experiment to test if CO2 is indeed the culprit we suspect it is. It only takes about 10g of RO to make a noticeable dent in the color change resin. I already have two cartridges so I think I will run two separate setups and see what I get.
Setup 1 is the degassing setup I currently have.
Setup 2 will be a 10g barrel with an air stone in it for 24 hours.
I'll measure how many fractions of inches of DI are depleted after the 10 gallons is produced and see if there is a noticeable difference between the two methods.
OP
OP
TheEngineer
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Just for reference my units are PPM.
Oh and this thread made the daily email yesterday (or was it the day before?) either way... Cool!
Oh and this thread made the daily email yesterday (or was it the day before?) either way... Cool!
Color changing resins are very inaccurate, I would not depend on color change for much if you are looking for accuracy. It can change in streaks, not at all, all at once, top to bottom, bottom to top and any number of things. It partially depends on how well the resin was bended when the cartridge was packed and on how well and tightly it was packed so the resins do not stratify. Use a good handheld ATC compensated TDS meter.
