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Post by h2otech on Dec 1, 2022 10:48:17 GMT
A little back story.... Sunday our carbon tanks were rebedded. Monday morning chlorine levels were <0.01 and well within standard. 2 hours into our morning, water quality began to suffer. Switched over to DIs. I did some investigating and pH was high post carbons. That evening I back washed tanks repeatedly until pH level was down to a manageable level. By Tuesday morning, conductivity 3us- rejection rate 98%. Everything was back to normal. Wednesday morning (5am), initial water quality was great and total chlorine levels were exactly what we are used to seeing- <0.01. Second check of the morning (9am), total chlorine level was at 0.02 and has stayed there since. My question is, why? What happened to see this sudden change? I know we are well below the 0.1 but this is not our baseline. I have reached out to municipal water source. They didn't do any hyperchlorination. I did check the tap water to see where the total chlorine level is standing. City water coming into us is 0.05. Any insight into this is greatly appreciated.
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joey
Full Member
Posts: 226
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Post by joey on Dec 1, 2022 12:12:24 GMT
Man .05 coming in and it is only bringing down to .02? Definitely something wrong.
Did you have outside vendor come? If so I would have them come back. When are they set to backflush automatically?
Personally it sounds like they weren't rinsed/dwelled enough when they were rebedded. Once the fines get on the membranes and throw the pH off you have to run that bad boy for awhile.
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Post by h2otech on Dec 1, 2022 12:54:52 GMT
I did the rebed myself. The most trouble I ever have is a leak here or there. I've never had something like this happen. Dwell was 6 hours. Back flushing is set for every 3 days. I did back flush the evening that I realized the pH was high. I back washed until pH came down. I just don't understand why it was good and then wasn't. I have spare fleck heads on site. I'm wondering if there isn't something going on with one of them- or both.
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Post by h2otech on Dec 1, 2022 12:57:56 GMT
I did the rebed myself. The most trouble I ever have is a leak here or there. I've never had something like this happen. Dwell was 6 hours. Back flushing is set for every 3 days. I did back flush the evening that I realized the pH was high. I back washed until pH came down. I just don't understand why it was good and then wasn't. I have spare fleck heads on site. I'm wondering if there isn't something going on with one of them- or both. I also checked levels of carbon in each tank. Just to make sure there wasn't something stuck wide open during a baskwash and my carbon blew out. There are no carbon fines in coming out the drain while back washing. Water is clear as clear can get. |
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Post by gfreely on Dec 1, 2022 16:15:34 GMT
Was the new material acid-washed?
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Post by h2otech on Dec 1, 2022 17:58:13 GMT
Yes it was acid washed carbon
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Post by dave74 on Dec 1, 2022 20:24:44 GMT
Years ago, we had exchange carbon tanks. The tanks were rebedded and exchanged by the vendor on a set schedule or if there was chlorine breakthrough, whichever came first. Every time the vendor exchanged the tanks, the R.O. percent rejection dropped. I complained to the vendor, but they claimed they were doing everything by the book. It would actually take several days for the percent rejection to come back to normal.
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Post by gfreely on Dec 2, 2022 12:43:51 GMT
The reason I asked is that, last year, our vendor exchanged our tanks with some which were re-bed with acid washed carbon and evidently they did not rinse them well enough. We had very similar issues. Other customers confirmed the same problem and advised to flush them to drain for several hrs. Did so and problem resolved.
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Post by h2otech on Dec 2, 2022 19:08:04 GMT
The reason I asked is that, last year, our vendor exchanged our tanks with some which were re-bed with acid washed carbon and evidently they did not rinse them well enough. We had very similar issues. Other customers confirmed the same problem and advised to flush them to drain for several hrs. Did so and problem resolved. So, if I were to put them in back wash and unplug the heads to continually backwash them, it should solve the problem? Or do you think we are stuck at a total chlorine level of 0.02? |
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Post by Chuck Weddle on Dec 3, 2022 15:52:06 GMT
If the backwashing doesn't fix it, my guess is your heads need to be rebuilt or replaced.
It doesn't take much to etch the housing or damage a seal.
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Post by h2otech on Dec 5, 2022 12:10:59 GMT
If the backwashing doesn't fix it, my guess is your heads need to be rebuilt or replaced. It doesn't take much to etch the housing or damage a seal. That's where my thought process was going. I will be changing them out this week. I have a spare for each tank on site and to be honest, I was initially going to replace when I did the carbon exchange. But then I figured, why fix something that isn't broke. I should have trusted my gut with this one, for sure. |
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Post by dave74 on Dec 5, 2022 13:31:51 GMT
How many total carbon tanks do you have? I was thinking you could check an individual carbon tank to see if it was the culprit.
You are going above and beyond what AAMI says you have to do. Going by AAMI standards, you don't have to do anything about a chlorine level of 0.02. Are you fixing a perceived problem that doesn't exist?
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Post by h2otech on Dec 5, 2022 17:53:37 GMT
How many total carbon tanks do you have? I was thinking you could check an individual carbon tank to see if it was the culprit. You are going above and beyond what AAMI says you have to do. Going by AAMI standards, you don't have to do anything about a chlorine level of 0.02. Are you fixing a perceived problem that doesn't exist? Dave, we have two banks of 2. Two workers, Two polishers. I'm going to isolate each one this evening and do just that. My concern is that I had one tank that the threads were questionable. I was able to get a tight seal but I'm afraid that if I take the head off one more time, the treads are going to give me a problem. At the time of rebed, I didn't have a spare tank to replace it and it seems getting anything delivered "on time" or drop shipped is almost impossible. This has been our experience, anyway. As for your second question....funny you should ask. I like to be proactive as opposed to reactive. Not a bad quality to have however, it does cloud my judgement at times. I guess the answer is I am most definitely trying to fix a perceived problem that doesn't exist. Sometimes coming here and getting the peace of mind is all I need.  |
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Post by motorsports on Dec 9, 2022 19:25:05 GMT
Years ago, we had exchange carbon tanks. The tanks were rebedded and exchanged by the vendor on a set schedule or if there was chlorine breakthrough, whichever came first. Every time the vendor exchanged the tanks, the R.O. percent rejection dropped. I complained to the vendor, but they claimed they were doing everything by the book. It would actually take several days for the percent rejection to come back to normal. We are currently having this same issue. It happened with brand new systems with exchangeable carbons where the RO membranes ended up being replaced under full warranty by the vendor, prior to system use, even. Also had this happen with backwashing 4 cubic foot carbons where a pair of lignite carbons was added pre carbon worker to resolve the total chlorine levels being greater than our base line of zero. Let us know if you learn anything from your efforts to resolve. we are ready for carbon exchanges and are a little concerned our RO water quality and volume will tank on us. |
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Post by dave74 on Dec 10, 2022 3:30:11 GMT
This goes way back in time, but a water vendor gave us a great price on exchange carbon tanks for home patients. As I remember it, we had problems. The per cent rejection dropped on multiple home patient ROs. The vendor kept telling us to rinse longer. I can't remember if the problem was the quality of the carbon or poor preparation of the carbon before sending the tanks to us. We changed vendors.
We also changed vendors for the outpatient unit. Things improved but weren't perfect. In some cases the vendor admitted that he just didn't have the time to soak the carbon for as long as he would have liked.
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