Hello We have a Barnstead Nanopure Diamond system and have a question about some inconsistency weve in water purity coming out of the system Here are the specific events that happened Our RO feed water system had some problems As a result the system was repaired During that repair process air was introduced into the RO lines that feeds our nanopure system Air was run into our nanopure system It is also possible that some subpar feed water came down the line as well We routinely about once per day check the conductivity of the RO feed water with a separate probe and never saw anything below normal our normal range is 27 Mohms A day or so following the RO work the resistivity of the water went down significantly from 182 to about 60 The first day this happened it was clear that enough air went into the nanopure system to be able to see it in the front cartridge After some time of flushingrecirculating about a day the air seemed to be gone The low water quality persisted still around 6 or 7 the same as the RO feed We assumed at this point that the filter cartridge was bad and ordered a new one The system sat mostly unused over a period of 34 days Before installing the new cartridges we turned on the system to test it It consistenly read 182 and has stayed there ever since without installing new cartridges We have verified the resistivity with an external probe and therefore trust the output water Given these events we have some questions
1 Would a bolus of air into the system cause this type of event to occur loss of water quality followed by a slow but total recovery
2 If this is caused by air is there some way to speed up the process to recovery What is the mechanism
3 If it is not caused by air is there some other event that could cause this to happen Could it be that a portion of the feed water had lots of particles or ions in it
4 If it is not caused by air again is there some way to speed up recovery Thank you for your help and insight Dan Stevens
Answer
What probably happened was that the deionizers inside the pack disassociated from non-use. You would then have to re-circulated it to get all the ions in the pack to re-align based on their molecular wt. If that takes a long time, the pack is probably near exhaustion. Air would not cause your problem, if anything the air makes the resistivity go high not low. They probably had some chemicals used while fixing or sanitizing the RO that got into your system. Recirculating at 18.2 isn’t the best measure, you would need to watch the resistivity as you draw off water. If it is high during recirculation but dips lower as you draw water, then your filter is very close to exhaustion and would need to be replaced. It is impossible to know what might have been in the water while they were fixing the RO. A reading of RO water in the megohm range doesn’t seem accurate sine most RO Systems can only reach about 0.1 megohm (about 5 p.p.m.) unless they have some special chemical injection and are double pass. It is important that when you measure conductivity or resistivity that it is done with a special temperature compensating meter. I am not sure what you use, but it would need to be specifically designed for measuring water.
Here is a link to the filters and operating manuals for your system.
Code F, 2.5 inch X 10 inch. Coconut shell carbon block with 10 micron outer wrap. Special Prep 1, for Chlorine removal with low extractable applications - 1/pk
Filter Housing
IWT 3C0600002 Style High Capacity Filter - Cartridge Universal II
This High Capacity Mixed Bed Deionization Filter is used for the reduction of dissolved minerals. with Color Indicator - Comparable to IWT and US FILTER 3C0600002 and HC200 or HC-200
Great for Lab Water Pretreatment
or Great Drinking Water
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