Does a 4 stage r/o unit remove chlorine and or chlorine dioxide?
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Old 02-12-2013, 06:42 AM   #1
Hardstuff
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Does a 4 stage r/o unit remove chlorine and or chlorine dioxide?


I just restocked my 10 gallon planted tank. It has been fish less for 10 weeks. It did contain 2 cherry shrimps & a small snail population that remained. I may have had a parasite problem in the past but not sure. The tank had its ups & downs, but has been stable & doing really well with plant growth. I even used a microscope to look for issues & could not find any although was able to see different protozoans, none looked parasitic.
The fish were in QT for 10 weeks in a plain separate tank . I did notice 1 out of 5 Amber Tertras did scratch 1 or 2 times a week before I let them run. I did not notice any scratching the last 5 days before they went into the show tank.
Now day 3 & after my 100% remineralized water change which was 50% change in volume, 1 fish maybe 2 scratched many times after the water change. I had an accident where I think I contaminated a dosing dropper with a tiny amount of ammonia earlier in the day. I immediately ran an ammonia test on the tank & it read zero but I dosed another 5 drops of prime into the tank to play it safe. Could that be causing the scratching or I have been suspicious that my R/O may be letting some chlorine & or chlorine dioxide through to the process water, causing my long term scratching issues with other fish! But I am not sure because the chlorine test kits are not in stores.
I dose prime even with the aged r/o water as a precaution at 1/2 dose or even less, sometimes only 2 or 3 drops per 3 gallons. Any guess about the chlorine passing the membrane or not. Puzzled! Best guess,thanks.
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Old 02-12-2013, 06:49 AM   #2
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Do you have a TDS meter? That's a quick and easy way to check the effectiveness of your RO unit. You should have very low (preferrably 0) readings from your RO water.
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Old 02-12-2013, 07:08 AM   #3
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I have a calibrated TDS meter. It shows a stable 23 reading, which if you run the math an average r/o rejects 96%-97% rejection. My Local tap runs around 530 so 97% rejection is about 23 at least within range. I am more concerned about the condition of my carbon. I do not even think I am running .5 more like 3 microns, & they are more than 6 months old with moderate usage. No R/O without deionizer stage will read zero. If you have soft water you can get close but zero is not realistic unless your meter is off. I have very hard water.
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Old 02-12-2013, 12:36 PM   #4
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I have a calibrated TDS meter. It shows a stable 23 reading, which if you run the math an average r/o rejects 96%-97% rejection. My Local tap runs around 530 so 97% rejection is about 23 at least within range. I am more concerned about the condition of my carbon. I do not even think I am running .5 more like 3 microns, & they are more than 6 months old with moderate usage. No R/O without deionizer stage will read zero. If you have soft water you can get close but zero is not realistic unless your meter is off. I have very hard water.
The more important question is how many gallons do you think you have ran through the Carbon block. That factor will better determine their condition.

When I re-mineralize with CaSO4 and a lot of it depending on my WC amount, I notice the scratching behavior. With CaCL2 on the otherhand I do not. IME when they get the itch it's usually for a few minutes randomly.

What are the ending results after you re-mineralize?
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Old 02-12-2013, 01:07 PM   #5
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The carbon prefilter removes chlorine.
And I've read that if chlorine is not removed by a prefilter, it will damage the RO membrane
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Old 02-12-2013, 05:01 PM   #6
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Thanks for the comments, they both are helpful.
I do use CaSo4 and also wondered if that contributed to the scratching. Between the CaSo4 & MgSo4 , KSO4 I often wondered if there is too much sulfur in my tank water which seems to me would be slightly acidic & could cause fish to scratch. I have been mixing my own Gh booster from planted tanks fertilizer instead of Seachems Equilibrium. My Gh is 5 Kh 3, TDS 200, Ph slightly alkaline. Maybe I should switch to a chloride. Has anybody else had similar experiences with the sulfur version when mixing booster?
I know there is sulfur even in the trace mix which would even add more sulfur.
I am going hunting with the microscope again today to see if I can find something but that is hit & miss. I feel it is more chemical than parasitic since it happens after water changes mostly.Thats why I felt maybe it was some chlorine getting past the membrane.
And yes I should replace my carbon soon as possible. Im thinking of switching to .5 micron carbons.
The question now is , should I switch to a chloride base booster???? Probably would not hurt. I have read that too much chlorides is bad for plants although I also read that is not true as well. Any further info would be great, thanks.
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Old 02-12-2013, 05:10 PM   #7
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I forgot to mention gallons used by the membrane. I am really bad at keeping track of that. I had the membrane & all the filters changed back last June. I have been testing the membrane & 23 is consistent with rejection in the process water. I was not using much water out of it until August when I got back into the hobby again. I usually replace all carbon 1 time a year when only using for drinking , but I plan on 2 times a year for carbon & just keeping an eye on the membrane . If it climbs over 25-30 range I will replace it. But keep in mind I am not running a resin stage at the end & without it I have very hard water & to expect 0 for a reading is not possible.
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Old 02-12-2013, 07:10 PM   #8
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Quote:
Originally Posted by Hardstuff View Post
Thanks for the comments, they both are helpful.
I do use CaSo4 and also wondered if that contributed to the scratching. Between the CaSo4 & MgSo4 , KSO4 I often wondered if there is too much sulfur in my tank water which seems to me would be slightly acidic & could cause fish to scratch. I have been mixing my own Gh booster from planted tanks fertilizer instead of Seachems Equilibrium. My Gh is 5 Kh 3, TDS 200, Ph slightly alkaline. Maybe I should switch to a chloride. Has anybody else had similar experiences with the sulfur version when mixing booster?
I know there is sulfur even in the trace mix which would even add more sulfur.
I am going hunting with the microscope again today to see if I can find something but that is hit & miss. I feel it is more chemical than parasitic since it happens after water changes mostly.Thats why I felt maybe it was some chlorine getting past the membrane.
And yes I should replace my carbon soon as possible. Im thinking of switching to .5 micron carbons.
The question now is , should I switch to a chloride base booster???? Probably would not hurt. I have read that too much chlorides is bad for plants although I also read that is not true as well. Any further info would be great, thanks.
Well I'm not exactly stating the CaSO4 is a problem, it's just an observation I've had over the years. It usually happens if I'm adding quite a bit of the compound, e.g., when I'm doing a reset (99% +) WC essentially going from 0ppm TDS to over 150~250ppm at once. I've never lost a fish due to it and if I remember correctly it was't all of them that would do this, some were more tolerant to this than others.

If you are changing 20~30% of the water you shouldn't be much of that flicking that they do going on. What percent WC do you do?

Using CaCL2 they say will cause a problem over time due to build-up, so I would do a 50/50 mix over straight up CaCl2

Quote:
forgot to mention gallons used by the membrane. I am really bad at keeping track of that. I had the membrane & all the filters changed back last June. I have been testing the membrane & 23 is consistent with rejection in the process water. I was not using much water out of it until August when I got back into the hobby again. I usually replace all carbon 1 time a year when only using for drinking , but I plan on 2 times a year for carbon & just keeping an eye on the membrane . If it climbs over 25-30 range I will replace it. But keep in mind I am not running a resin stage at the end & without it I have very hard water & to expect 0 for a reading is not possible.
They say to get the 10,000gals 0.5~.6 micron is the way to go, and ~3000gals for those 5 micron blocks. I currently use 2 5 micron Carbon Block and have put about ~1500gals through them and still no Chlorine present. I do have .06 Micron blocks, but have not have the need for them yet.

If you barely put any water through it even though it's been sitting I wouldn't worry about it. Age is not the factor, it's the gallonage that depletes it.
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Old 02-13-2013, 05:56 AM   #9
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Thanks mrkookm: I estimated I have run 800-900 gallons through the membrane to this point. That may not sound like a lot but I have very high chlorine + chlorine dioxide which is a gas. The water untreated smells like a swimming pool! I do not trust the 5 micron filters & without a chlorine test kit that is not a strip I really do not know if all the chlorine has been neutralized. I was wondering if you or others treat the process water with a conditioner as a back up so to speak after R/O treatment.
I lost a long time ago a batch of fish because of chloramines when I switched distributions. 20 fish died in a matter of minutes (not using R/O). Im not saying for sure that my problem is chlorine at all but it could be. I was also wondering about Prime water conditioner irritating fish as well. The guy at the filter company said it is possible.
In my case the latest situation the fish could have flashed because of me accidently dosing a tiny amount of ammonia like I stated earlier.
I watched the fish tonight & they all looked fine & were swimming around acting happy. But I am a half empty guy. I get the feeling the flashing will come back at the next change or sooner. A guy at work with chem experience said that chlorides are more reactive than sulfates, & he suggested staying with the sulfate based fertilizers stating the reactivity of chlorides.
Mrkookm, I did not understand that TDS change you were talking about,99% something like 0 to 150-200 that is huge, why would subject the fish to that?
Although I just transfered my last fish into the 10 last night not realizing that earlier would have been better. The fish went from 7.8 to 6.4 head down fins jerking at the bottom of tank. Thought I lost it then tried dangerously raising the Kh slowly which would cause a rise in ph. It took 20 minutes & the fish just snapped out of it & joined the group like nothing happened. The TDS was only 30 of a difference.
What about Fe, Ferrous Gluconate? I dose 4 or 5 drops per day. If not that what about Prime causing flashing? Too much sulfates combined with all the other fertilizers. Lastly chlorine. Take your pick. Thanks
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Old 02-15-2013, 04:41 AM   #10
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Update on flashing cause. Today I dosed only Fe & separate Trace elements also containing Boron. This time I actually mixed the Fe & Trace in a small container to dilute it further. Then I emptied the contents slowly to spread around the aquarium. I held it up to a wide spectrum light to see how strong it looked before dosing. It looked only slightly yellow brownish to the eye. 3 drops of Fe + 3 drops of trace. No scratching was observed all day, however within moments 1 fish flashed on a plant gently twice within 5-20 seconds ; then the flashing stopped, but it was only 1 fish. I watched the fish for along time hours latter & observed zero flashing.
Does this mean it was the fertilizer? Probably. Tomorrow I will dose only KNO3 & KPO4 just enough to spike the tank to 10ppm of nitrate & 1 ppm of PO4 & see what happens. I will not dose Fe or Trace.
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Old 03-02-2013, 01:54 PM   #11
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Quote:
Originally Posted by Hardstuff View Post
I just restocked my 10 gallon planted tank. It has been fish less for 10 weeks. It did contain 2 cherry shrimps & a small snail population that remained. I may have had a parasite problem in the past but not sure. The tank had its ups & downs, but has been stable & doing really well with plant growth. I even used a microscope to look for issues & could not find any although was able to see different protozoans, none looked parasitic.
The fish were in QT for 10 weeks in a plain separate tank . I did notice 1 out of 5 Amber Tertras did scratch 1 or 2 times a week before I let them run. I did not notice any scratching the last 5 days before they went into the show tank.
Now day 3 & after my 100% remineralized water change which was 50% change in volume, 1 fish maybe 2 scratched many times after the water change. I had an accident where I think I contaminated a dosing dropper with a tiny amount of ammonia earlier in the day. I immediately ran an ammonia test on the tank & it read zero but I dosed another 5 drops of prime into the tank to play it safe. Could that be causing the scratching or I have been suspicious that my R/O may be letting some chlorine & or chlorine dioxide through to the process water, causing my long term scratching issues with other fish! But I am not sure because the chlorine test kits are not in stores.
I dose prime even with the aged r/o water as a precaution at 1/2 dose or even less, sometimes only 2 or 3 drops per 3 gallons. Any guess about the chlorine passing the membrane or not. Puzzled! Best guess,thanks.
As far as chlorine - nearly all RO systems these days use membranes made of a TFC material. This material can not withstand exposure to chlorine - so you will always see a carbon prefilter on these systems - the carbon removes the chlorine before the water reaches the membrane.

Additionally, chlorine volatilizes easily - so if by some wild chance you ended up with chlorine in your RO water, aging the water as you mentioned would allow the chlorine to volatilize. So no need to add a dechlorinator (e.g., "prime").

Russ
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Old 03-02-2013, 01:59 PM   #12
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Quote:
Originally Posted by sarahspins View Post
Do you have a TDS meter? That's a quick and easy way to check the effectiveness of your RO unit. You should have very low (preferrably 0) readings from your RO water.
RO membranes, depending upon the brand and specs on your particular membrane, typically remove 90% or more of the TDS in the feedwater. So for example if your feedwater reads 160 ppm, your RO water should read 16 ppm or less. Given this, you are unlikely to see RO water read 0 ppm TDS. Here are some specs on widely used membranes. The column for "rejection" describes the % of TDS reduction that can be expected:



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Old 03-02-2013, 02:02 PM   #13
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And yes I should replace my carbon soon as possible. Im thinking of switching to .5 micron carbons.
That's fine, but if you do, make sure you use a sediment filter @ 1 micron or less. Otherwise your carbon block will behave like a sediment filter.

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