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RO unit possibly allowing chlorine or chloramine through


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Been having deaths across my shrimp tanks particularly after water changes , seems it's possible because I never replaced my filters and DI resin that chlorine or chloramine may be getting through to my collecting containers , any one else had this or got any info would be welcomed , I am due delivery of filters etc, been suggested to use prime

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RO units use carbon block filters to remove clorine and cloramines from water.  They only are effective for so many gallons and they vary on service life.  Sorry you have lost shrimp, and yes use prime until you get a new carbon block.

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Been having deaths across my shrimp tanks particularly after water changes , seems it's possible because I never replaced my filters and DI resin that chlorine or chloramine may be getting through to my collecting containers , any one else had this or got any info would be welcomed , I am due delivery of filters etc, been suggested to use prime

 

 

My observations have shown that even though the replacement water is exactly spot on, just the act of changing water will cause deaths.

 

I now change only 10% at a time and replace the water at a very slow drip of about one drop per second. I use a 1 liter cup to siphon feed the drip so that I don't overfill the tank because it takes all day to drip the water back in. So far this method has resulted in zero deaths.

 

My tank is only 2.5 gallons, so if you try this and your tank is larger you will want to speed up the refill drip rate.

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You can simply measure tds of the water coming from the filter to see how good it works. I always checking my ro water tds and if it rase above 7-9 I removing cartridge with resin and check again to see if other cartridges are still good, if then tds is below 15 I only change resin or if above I change them all. I only changed all cartridges once and they last almost two years and I have very hard tap water but I'm changing resin once a three months or so. I'm using about 50-70L of ro weekly.

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You can simply measure tds of the water coming from the filter to see how good it works. I always checking my ro water tds and if it rase above 7-9 I removing cartridge with resin and check again to see if other cartridges are still good, if then tds is below 15 I only change resin or if above I change them all. I only changed all cartridges once and they last almost two years and I have very hard tap water but I'm changing resin once a three months or so. I'm using about 50-70L of ro weekly.

 

 

I agree with Citycode01 - I have an In-Line Dual TDS Monitor that is connected before and after the DI resin filter because the resin doesn't last long.

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When the resin goes bad, can you be able to tell simply by seeing an increase in TDS?  Can a resin go bad without seeing this increase?

Yes. The first time I used DI Resin, I was not aware how fast it would deplete. Out of curiosity I checked the TDS in and out after a couple months and found the TDS IN was 6ppm (from RO membrane), and the TDS OUT was 59ppm. So it looks like the DI resin will start to dirty the water when it's depleted.

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TDS meters will not tell you if there is chlorine or choramines in the water.  They measure conductivity only, and these chemicals are non conductive. I am sorry, but this whole changing water kills shrimp bugs the heck out of me as well.  If the water you use for changes is the same tempature, the same ph and matches closely in the content of dissolved solids and does not contain chemicals that harm aqautic life, it will not kill your shrimp no matter how much you change.  There is nothing wrong with slow dripping the water if it does not match everything perfectly and it is always best to be cautious of course but new water could be replaced continuously as long as the above conditions are met.  Back to carbon blocks.  The only way to know if they are still working to remove any said chemical is to test the water with the the appropriate test kit.  They have a life period and can only absorb so much before they are exhausted.  I really don't mean to upset anyone here but that is just the way this stuff works and there is too much misinformation on the net these days where we can all learn things incorrectly.


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Yes. The first time I used DI Resin, I was not aware how fast it would deplete. Out of curiosity I checked the TDS in and out after a couple months and found the TDS IN was 6ppm (from RO membrane), and the TDS OUT was 59ppm. So it looks like the DI resin will start to dirty the water when it's depleted.

This is correct.  A triple inline meter on your RODI system can give you a good idea if the DI resin is exhausted.  In fact color changing DI resin can still be OK for a period of time after the color changes.  If the DI resin is working right you should have 0 tds.

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TDS meters will not tell you if there is chlorine or choramines in the water.  They measure conductivity only, and these chemicals are non conductive. I am sorry, but this whole changing water kills shrimp bugs the heck out of me as well.  If the water you use for changes is the same tempature, the same ph and matches closely in the content of dissolved solids and does not contain chemicals that harm aqautic life, it will not kill your shrimp no matter how much you change.  There is nothing wrong with slow dripping the water if it does not match everything perfectly and it is always best to be cautious of course but new water could be replaced continuously as long as the above conditions are met.  Back to carbon blocks.  The only way to know if they are still working to remove any said chemical is to test the water with the the appropriate test kit.  They have a life period and can only absorb so much before they are exhausted.  I really don't mean to upset anyone here but that is just the way this stuff works and there is too much misinformation on the net these days where we can all learn things incorrectly.

Chlorine and Chloramine are both molecules and carry no charge. Conductivity is a function of charged substances. However, the addition of chlorine as CL2 (g) to water produces hypochlorous acid and some of Chloramine can also break down into this;

Cl2 + H2O -> HCl + HOCl

The hypochlorous acid then ionizes to hypochlorite:

HOCl <-> H+ + OCl-

So this will give some conductivity.

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Sounds like you really know your stuff and I would like to learn more. The above formulas are correct however I was taught that these ions have too weak of a charge to be detected by a TDS meter so what am I missing here?

The main point I really want to make here is never use a TDS meter to guess or assume there is no chlorine or any other substance in your water. You can not use it to guess if your carbon block is good. Àlso from what I understand if chlorine passes to your RO membrane it can trash it fairly fast which will cause a high TDS reading due to it not working anymore, and likely will need replacement as well.

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Thank you for all the input, special thanks to gillsnglass for the following information, I have always had zero TDS and I believe my ignorance in the science of RO units has been my mistake , due replacement filters and in future will change them early rather than late no matter what zero TDS it shows. Since I treated with tetra aquasafe as an emergency measure I have only lost one shrimp but then damage will have been done , I have tried all sorts of water changes from jug in and out to drip all never helped it's talk of water changing I believe through me off trail, below is a most valuable info which I also has confirmed by a reef expert who has an RO buisness

TDS meters will not tell you if there is chlorine or choramines in the water. They measure conductivity only, and these chemicals are non conductive. I am sorry, but this whole changing water kills shrimp bugs the heck out of me as well. If the water you use for changes is the same tempature, the same ph and matches closely in the content of dissolved solids and does not contain chemicals that harm aqautic life, it will not kill your shrimp no matter how much you change. There is nothing wrong with slow dripping the water if it does not match everything perfectly and it is always best to be cautious of course but new water could be replaced continuously as long as the above conditions are met. Back to carbon blocks. The only way to know if they are still working to remove any said chemical is to test the water with the the appropriate test kit. They have a life period and can only absorb so much before they are exhausted. I really don't mean to upset anyone here but that is just the way this stuff works and there is too much misinformation on the net these days w

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It's always a good idea to let your ro water age for couple of days in case if any chlorine or chloramine in it or even run an air stone.

Gillznglass I think we can have a simple experiment and measure tds of the tap water straight from the tap and after two days being in open container and see if tds will drop or stay the same.

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It's always a good idea to let your ro water age for couple of days in case if any chlorine or chloramine in it or even run an air stone.

Gillznglass I think we can have a simple experiment and measure tds of the tap water straight from the tap and after two days being in open container and see if tds will drop or stay the same.

Cool idea! I am on well water though. Do you mind performing this? Wygglz said she would bring some water from work in town that has the nasty stuff in it sealed bottle of course. I'm not sure if they use chlorine or chloramines, but I do have test kits for it that came with my ro system. So if you like let's both try it and report back here. I will post what meter I have as well. I have 2 different brands so I may try both. Science geek hat on.

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Cool idea! I am on well water though. Do you mind performing this?

Sure I will fill the jar with tap and do a first measurements in a minute. I have just a second thought there are some other components that can be affect tds and evaporate during some time. For instance co2 dissolved in water make H2CO3 which will dissociate to HCO3− and H+ and we know that the water straight from the tap contain a lot of co2 this will probably give us a drop of tds for sure.
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Sure I will fill the jar with tap and do a first measurements in a minute. I have just a second thought there are some other components that can be affect tds and evaporate during some time. For instance co2 dissolved in water make H2CO3 which will dissociate to HCO3− and H+ and we know that the water straight from the tap contain a lot of co2 this will probably give us a drop of tds for sure.

To bad we can't get pure chlorine and add it to 0 Tds RODI at the same ppm allowed in city water.

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What I'm doing is checking when the city will add more chlorine to the water -usually June and December here in Florida.

When the time come I'm treating already clean RO with 1/2 dosage of prime just in case.

Other thing is that I added one more carbon stage to RO unit.I'm changing sediment and 2x carbons every 6 months. I'm producing 60-90gal RO water a week.

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