RO/DI decision time

[AZDesertRat]

Chloramines mean you need a very good carbon block like a 0.5 micron Matrix Chlorine Guzzler or catalytic carbon folowed by a good carbon block and a high quality DI. By high quality I mean a vertical 20 oz 10" canister type with a nuclear or semiconductor grade mixed bed resin. The carbon removes the chlorine portion and the DI removes the ammonia that gets by the RO membrane.

 

[Fishbulb2]

I'm not surprised you have chloramines in your water since I am also in SoCal and they use it here. Definitely use the highest quality carbon blocks that you can. What I do to help prevent any chlorine break through is to increase the contact time between the water and the carbon block. I do this by having a second carbon block. So my prefilters run sediment, carbon 1, then carbon 2. To prevent from having to replace twice as many carbon filters , I rotate and replace the carbon blocks every 6 months. What I do is throw carbon block 1 away in the trash and move carbon block 2 up into the first position. I then add a second carbon block behind it. This way I always have a fresh carbon block in position 2 and the block in position 1 is still relatively fresh (since it was previously shielded). I measure the chlorine in my waste line periodically and have not had a break through yet. It's also amazing the difference in discoloration between the first and second carbon blocks. I think the back up block is a good idea and safety measure for those with chloramines in their tap water.

FB

 

[five.five-six]

ok I am ordering a "Catalytic Carbon stage to split the chloramine to products more readily removed by the remaining stages in the system"

but my question is, how bad is this stuff?

would it have anything to do with a few mystery "Poof that frag went white" episodes I have had?

 

['06Siguy]

Great info in here. I'm really glad I found it. I just hooked up a RODI I got with my tank. It seems to be working good. A couple wuestions though... When not in use, the DI chamber is full of water, but as I open the product valve, it empties on the outside of the cylinder.

Also, is this a good membrane? You said there was higher TDS with larger membranes, so how does this rate?
http://theh2oguru.zoovy.com/product/TW301812-150

Thanks.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11782270#post11782270 target=_blank>Originally posted</a> by five.five-six
ok I am ordering a "Catalytic Carbon stage to split the chloramine to products more readily removed by the remaining stages in the system"

but my question is, how bad is this stuff?

would it have anything to do with a few mystery "Poof that frag went white" episodes I have had?

I would REALLY go with two standard .5 um chlorine guzzler type carbon blocks instead of the refillable loose activated carbon variety. The carbon blocks will be a lot easier to use, probably have less carbon dust, and will certainly provide you with enough protection (especially if you double up on them as I described). Jim from filterguys suggested this to me and I'm glad I went this route without dealing with the activated catalytic carbon.

If the water you were using before had chloramines still in it when you added it to the tank, then yes, it could explain a lot of death. Chloramines are also worse than chlorine gas because it will not off gas by leaving your water out or aerating the water.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11782297#post11782297 target=_blank>Originally posted</a> by '06Siguy
Great info in here. I'm really glad I found it. I just hooked up a RODI I got with my tank. It seems to be working good. A couple wuestions though... When not in use, the DI chamber is full of water, but as I open the product valve, it empties on the outside of the cylinder.

Also, is this a good membrane? You said there was higher TDS with larger membranes, so how does this rate?
http://theh2oguru.zoovy.com/product/TW301812-150

Thanks.

The fact that your DI chamber empties on the outside when you draw DI water is no problem at all. The water is still forced through the resin via then internal chamber of the cannister. This is common and not something to worry about.

That membrane is also sold at buckeyefield supply and appears to be becoming more popular. It's generally advertised as a 98% rejection rate but virtually no one has ever reported their actual rates here on RC. Thus I don't really know. If you can get by with a 75GPD filmtec membrane, it is probably a more "sure" thing. At least you can get dozens of users input here on RC. I may try that same membrane sometime in the future if I start seeing positive reviews about it but until then I'll stick with my spectra select membrane. At least, I would contact the vendor and tell them you are interested in the membrane. Ask them the rejection rate and what minimum rejection rate would you need to return the membrane as defective. If they say anything less than 96%, I think I would just stick with the proven Dow membrane.

FB

also there is someone here that is running two of these membranes so he may be able to tell you what rejection rate he gets on each of them

 

[AZDesertRat]

When you can get a good 150 GPD membrane they are great. I have one from Spectrapure that they were able to get to pass their rigourous testing to become a Select Series 98+% rejection rate membrane. Unfortunately they quit carrying them as they were not able to get a large enough supply of them to pass their testing procedures. Mine was one of the first and it has been 99.23 to 99.35% rejection ever since May 07. I do believe just like other membranes though this is a rare exception, 96-98 is probably the best you can expect and probably closer to the 96%.

 

[beanoil]

Forgive me for stepping in on a great thread, but I think this may help the OP as well. Fishbulb and AZDesertRat, you've confused me on the permeate pump. I too am using a pressurized storage tank hooked up to an icemaker. I bought an RO/DI unit from one of the RC sponsors mentioned above (1 sediment, 2 carbon, 100gpd membrane, 10" vertical DI canister), and I'm getting 8 gallons of waste to 1 gallon of good. I've been thinking that it has something to do with the pressure tank. Is a permeate pump the fix, and if not, any idea what is? Again, thanks for the great info here.

 

['06Siguy]

Well I did buy that membrane and am useing it now. When I received my reefkeeper unit, it didn't have a membrane, so I figured since it says 98%, I'd be fine. I don't have any test equiptment though. How much are those handheld unit you were talking about?

Also, I know TDS stands for total dissolved soilids or something, but I was wondering how important it is to have it at 0. Let's say my membrane is only getting 96 like someone had said earlier...does that just mean I'll go through the resin sooner? What if I did a by-pass on DI and put the 96% water into my DT. What would be the outcome? I think I'm starting to understand this stuff. It's a lot to take in though. But thanks again for the great info!

 

['06Siguy]

Oh, nevermind about the testing units, I found some at airwaterice.com they're not as expensive as I thought they'd be.

Thanks again for the help.

 

[AZDesertRat]

The 8:1 waste is easily cured with the correct flow restrictor. You would also benefit from a permeate pump though as you can read here. It actuality I don't believe the savings are as dramatic as they claim but it is a definite improvement and every little bit helps.
http://www.watertec.com/e/erod-030.htm

I would say a good handheld TDS meter is a must if you have an RO/DI unit. I don't know what I would do without it. Meters can be had for as little as $20 but I highly recommend the HM Digital COM-100 since it is 10x more sensitive and accurate. It can be calibrated in three different modes and has extremely high low level accuracy. They can be had for about $50 most places.

TDS is Total Dissolved Solids you are correct. Its basically a measurement of everything in the water that is electrically conductive measured in parts per million (PPM). It is not as accurate as conductivity or resistivity measurements but for our purposes it works well and the instruments are affordable. The COM-100 even measures conductivity and temperature unlike other meters. You want 0 or as close to it as possible, there is absolutely no reason a decent RO/DI unit with fresh DI resin and a true RO membrane cannot achieve 0 TDS at least for a while. Better membranes and better DI resin will give you 0 TDS for longer periods thus end up being a cost savings over the long haul. It pays to buy the best you can afford as you end up replacing it less often.

Adding water with nominal TDS readings to your display is probably not going to kill anything right away but you must remember lots of electrically conductive contaminants are cumulative meaning they never go away and may not be reduced with water changes. Some things like copper get into the rocks and sand and you never get rid if it once its there. Its best to ensure it does not get there in the first place.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11782744#post11782744 target=_blank>Originally posted</a> by beanoil
Forgive me for stepping in on a great thread, but I think this may help the OP as well. Fishbulb and AZDesertRat, you've confused me on the permeate pump. I too am using a pressurized storage tank hooked up to an icemaker. I bought an RO/DI unit from one of the RC sponsors mentioned above (1 sediment, 2 carbon, 100gpd membrane, 10" vertical DI canister), and I'm getting 8 gallons of waste to 1 gallon of good. I've been thinking that it has something to do with the pressure tank. Is a permeate pump the fix, and if not, any idea what is? Again, thanks for the great info here.

I assume that you are using your RO/DI unit for both reef water and for drinking water (which is why you have the pressurized storage tank). When you make your DI water for your reef, are you drawing pressurized water from the storage tank or turning the storage tank off and collecting water as it is slowly made by the unit (100GPD in your case)? Are you measuring the 8:1 ratio when the unit is filling the storage tank or are you recording this ratio with the storage tank off allowing the unit to make water with no back pressure?

This is what I would recommend. Turn off your storage tank and allow the unit to run. The flow should now be a slight steady stream (100 GPD for you). Now measure the waste to good ratio. This is the ratio set by your flow restrictor. If it is greater than 4:1 then you may want to consider getting a new flow restrictor like the capillary style and adjusting it to give you 4:1 ratio. It is likely that with the colder temperatures now, that you will get worse than 4:1. This is why AZ previously recommended having two capillary restrictors. One that is adjusted for summer temps and one for winter temps. Then just swap them out as the seasons change. Now that you've done this, your unit is optimally calibrate to waste the least amount of water under normal conditions.

Now, open your pressurized storage tank and allow it to fill. The ratio of waste to good should have drastically gone up. This increase in waste water from 4:1 (which you just tested under non-pressurized conditions) is caused entirely by the back pressure of the storage. The permeate pump will return the ratio back down to 4:1.

I can't make a blanket recommendation for you b/c I don't know yet what the waste ratio of your system is yet without the pressure tank. It might do you even more good (in regards to water conservation) to calibrate your flow restrictor. A permeate pump will THEN insure that this ratio is maintained when the system is then hooked to the storage tank.

I can't tell, was that coherent?
FB

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11782815#post11782815 target=_blank>Originally posted</a> by '06Siguy
Well I did buy that membrane and am useing it now. When I received my reefkeeper unit, it didn't have a membrane, so I figured since it says 98%, I'd be fine. I don't have any test equiptment though. How much are those handheld unit you were talking about?

Also, I know TDS stands for total dissolved soilids or something, but I was wondering how important it is to have it at 0. Let's say my membrane is only getting 96 like someone had said earlier...does that just mean I'll go through the resin sooner? What if I did a by-pass on DI and put the 96% water into my DT. What would be the outcome? I think I'm starting to understand this stuff. It's a lot to take in though. But thanks again for the great info!

I would highly recommend trying to get your TDS down to zero before adding the water to your system. While most TDS is comprised of harmless ions like sodium, chloride, magnesium, and such, TDS is also comprised of nutrients for algae such as phosphates and nitrates. These compounds (NO3- and PO4-) are far less electronegative than chloride for example so DI resin will preferentially remove the Cl- and RO membranes won't remove them efficiently. Once the DI resin exhausts it will most likely exchange the NO3- and PO4- bound to it for the more electronegative Cl- and thus can start to add these nutrients back to the tank. Measurements of TDS will not tell you which ion species are present in your water and therefore cannot let you know what you are allowing to pass and what you are removing when you still have TDS after your RO or RO/DI. Ideally, once you have gone through the efforts to set up a proper RO system, adding the DI will still make you water substantially more consistent for a minimal extra investment.

FB

 

[five.five-six]

see, 3 pages and i am still not SURE what I need, this is why I sat out in the rain with buckets and quarters for so long. this is just so darnd confusing

looks like I am getting a system from Buckeye Field Supply the 75 gpd Reef/Residential RO/DI System + a Chloramine stage and some gauges and meters so I can operate the thing... do I need a flush kit? this thing is more complicated than my ACIII

 

[beanoil]

The 8:1 waste is easily cured with the correct flow restrictor. You would also benefit from a permeate pump though as you can read here. It actuality I don't believe the savings are as dramatic as they claim but it is a definite improvement and every little bit helps.

I assume that you are using your RO/DI unit for both reef water and for drinking water (which is why you have the pressurized storage tank). When you make your DI water for your reef, are you drawing pressurized water from the storage tank or turning the storage tank off and collecting water as it is slowly made by the unit (100GPD in your case)? Are you measuring the 8:1 ratio when the unit is filling the storage tank or are you recording this ratio with the storage tank off allowing the unit to make water with no back pressure?

The ratio when filling the pressure tank is about 8:1. With the tank valved off and the unit making RODI only, it's about 6:1. It seems like you're both recommending a different flow restrictor. Showing my ignorance here, I'm not really sure where to find it or what it looks like. Is it part of the ASOV? Also, if I'm understanding correctly, I'll benefit from the permeate pump as well, correct? Thanks again.

 

['06Siguy]

<a href=showthread.php?s=&postid=11783719#post11783719 target=_blank>Originally posted</a> by beanoil
The ratio when filling the pressure tank is about 8:1. With the tank valved off and the unit making RODI only, it's about 6:1. It seems like you're both recommending a different flow restrictor. Showing my ignorance here, I'm not really sure where to find it or what it looks like. Is it part of the ASOV? Also, if I'm understanding correctly, I'll benefit from the permeate pump as well, correct? Thanks again.

look here on the bottom of page...

http://www.thefilterguys.biz/ro_membranes.htm
^^

On that note, I bought that 150 GPD membrain, but didn't replace the restrictor. The restrictor says 800 on it...if that means anything. Would the membrane be more effective if the flow was restricted more than it was rated for? I.E. have a 150 membrane with a 90 restrictor. Or would that cause problems? Where can I find a flow restrictor for my 150 GPD?

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11783719#post11783719 target=_blank>Originally posted</a> by beanoil
The ratio when filling the pressure tank is about 8:1. With the tank valved off and the unit making RODI only, it's about 6:1. It seems like you're both recommending a different flow restrictor. Showing my ignorance here, I'm not really sure where to find it or what it looks like. Is it part of the ASOV? Also, if I'm understanding correctly, I'll benefit from the permeate pump as well, correct? Thanks again.

You want a capillary style restrictor as seen here about half way down.

http://www.buckeyefieldsupply.com/showproducts.asp?Sub=109&showspecials=109

You want one for 100GPD if that is what your membrane is rated for. I would get a few if I were in case you make any mistakes. They are not associated with the ASOV but rather insert into the drain line on the membrane housing. The longer the capillary tube, the more restrictive, the lower the ratio of waste to good water. So you will install the restrictor and then measure the ratio. Now if there is not enough waste water, then pull out the restrictor and trim it. Now the ratio should be closer to 4:1. Keep repeating this cycle of trimming and retesting until you achieve the desired ratio. Remember two key things, as you trim you will get more waste to good and make sure you do this testing with the storage tank closed off so that the unit is operating without back pressure. Then yes, the permeate pump will definitely allow you to waste less water while filling the pressurized storage tank.
FB

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11783693#post11783693 target=_blank>Originally posted</a> by five.five-six
see, 3 pages and i am still not SURE what I need, this is why I sat out in the rain with buckets and quarters for so long. this is just so darnd confusing

looks like I am getting a system from Buckeye Field Supply the 75 gpd Reef/Residential RO/DI System + a Chloramine stage and some gauges and meters so I can operate the thing... do I need a flush kit? this thing is more complicated than my ACIII

Just keep asking questions until you are no longer confused. You can always call buckeye too and the one on one conversation might help answer some of your questions.

Regarding flush kits: I don't believe their use has been proven, tested, and verified to exhaustion. Lots of people swear by them I'm not really sure how many people have really done anything scientific regarding testing. A typical membrane will last for five years easy so how long would this test take? I don't know of any reports showing so many years of data with and without the flush valves installed. That being said, they are relatively very cheap and very simple to operate. Therefore I went ahead and got one and use it regularly. If it actually extends membrane life, then great for me! If it doesn't, then I am really only out about $12 or so.

FB

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11783810#post11783810 target=_blank>Originally posted</a> by '06Siguy
look here on the bottom of page...

http://www.thefilterguys.biz/ro_membranes.htm
^^

On that note, I bought that 150 GPD membrain, but didn't replace the restrictor. The restrictor says 800 on it...if that means anything. Would the membrane be more effective if the flow was restricted more than it was rated for? I.E. have a 150 membrane with a 90 restrictor. Or would that cause problems? Where can I find a flow restrictor for my 150 GPD?

I believe you should have replaced the flow restrictor but this is easy to test for. Simply turn off your storage tank (if you have one) and measure the waste to good ratio. If it is less than 4:1, that is if you are flushing the membrane with less than 4 gallons of waste to each gallon of good, then you NEED to replace the restrictor. The waste water serves to flush the membrane and removes all of the TDS that is rejected by the membrane and sends it down the drain. As you go lower than the 4:1 ratio, the membrane begins to clog and will prematurely fail. Definitely measure this ratio and adjust for it accordingly.

FB

 

[beanoil]

You want a capillary style restrictor as seen here about half way down. You want one for 100GPD if that is what your membrane is rated for. I would get a few if I were in case you make any mistakes. They are not associated with the ASOV but rather insert into the drain line on the membrane housing. The longer the capillary tube, the more restrictive, the lower the ratio of waste to good water. So you will install the restrictor and then measure the ratio. Now if there is not enough waste water, then pull out the restrictor and trim it. Now the ratio should be closer to 4:1. Keep repeating this cycle of trimming and retesting until you achieve the desired ratio. Remember two key things, as you trim you will get more waste to good and make sure you do this testing with the storage tank closed off so that the unit is operating without back pressure. Then yes, the permeate pump will definitely allow you to waste less water while filling the pressurized storage tank.

OK, that's what I'll do. Thanks for the help.