Quick RODI unit questions

[Opus]

Considering that I have chloramine treated water, I'd love to hear what you all suggest for either a new RODI unit (do I need multiple resin chambers?) or:

New membrane (maybe I'll go back to one)
Should I use catalytic carbon? Brand?
A regular carbon block (which one)? Or BRS Universal block?
A chloramine carbon block (which one - Matrikx chloraguard? 1 micron?)
And which DI resins if I use more than one?

I looked at the Spectrapure MaxCap, but it isn't chloramine specific, so I need to find one that is (or change out the filters)... Thanks,
--Kyle

Personally, I would just make changes to what you have. I would go with a 1 micron pre-filter. The zetazorb is most likely overkill. The prefilters will not lower tds, at least not with any significance. You have to realize the ro membrane is rated at .0001 microns. Then I would go with 2 carbon filters. You can do a BRS universal followed by their VOC or do a chloramine specific filter followed by a normal carbon filter. I would then ditch the dual membranes and go with just one. The dow filmtec 100gpd is now rated at 98% rejection so is a good choice or the 75 gal is also good and many seem to get 99% rejection rate with it. Also get a new flow restrictor. You can get the barrel type that you match the part to the gpd rated membrane you are buying. These just plug into the tubing but you can’t adjust them. There is also the capillary style that slides inside the tubing and you trim to change the flow but if you mess up you have to buy a new one. Third option is to buy a valve that allows you to make small changes to the flow. That way you can easily regulate the flow restriction. It all comes down to personal preference.

You are currently seeing ammonia because the chloramine is being broken down by the carbon filter to chlorine and ammonia. The ro membrane does a horrible job at removing ammonia. That is the job of the di filter. In your case it appears the di filter is not working correctly between the ammonia reading and the tds reading. My guesses are it was not packed correctly, the di cartridge was installed upside down (been there, done that), or the media was bad.

The cation media is what will remove the ammonia. I would personally make all the changes above and just go with normal dual di media and see if that works but that is up to you. You can run a canister of cation before the dual di media to make sure it removes the ammonia.

Also ditch the auto shut off kit and add a flush kit that allows you to bypass the di media so you can get rid of tds creep. It is recommended you run the ro unit for a few minutes without running it thru the di media because the tds coming from the membrane will be really high for the first few minutes. It is basically a switch that allows you to switch the product water from the membrane between the waste water line and the di media line.

 

[Saltyreef]

True, or he’s outside, or close to, psi parameters

Would this be in relation to my comment of my system?
Im operating at 50-60psi. My concentration is inside spectrapures recommendation at 3x to 5x. If over 6x then there is an issue that would need correction.
I have two extra full size flow restrictors i could trim use to obtain less waste water but at the expense of my filters....
But i dont have an issue with my system it works great right from the box.

 

[Saltyreef]

Absolutely a possibility as well, either case would require a new one to adjust to his specific specs which is why I don't like that they send pre-trimmed restrictors when they should send full ones so the purchaser can adjust them to there unique water supply situations

They sent me two extra ones free of charge.

 

[kyley]

I would talk to their customer service to ensure you can get it installed prior to shipping. Also, i would skip adding a flush kit and just install the DI bypass valve to flush the unit properly.
...
Have you measured total and free chlorine to get a better understanding of to what PPM your chloramines are?

Thanks @Saltyreef. I've been chatting with Daniel a lot about their systems. I'm a little torn here. They make a lot of great claims about their filters, membrane, and DI resins. And I think they truly are focused on top quality products. But, they're also a lot more expensive on their replacement filters, and as an aquarium-specific company, I'm sure BRS is also trying to provide high quality filters and DI resins.

No, I haven't tested chlorine and chloramine. From what I've seen, the test strips are very inaccurate anyway.

To further expand on the chloramines will not hurt the OPs membrane, according to his water reports, 1 of the sources averages 2ppm of chloramines. Since there are 3 sources total, that will be lower. That means his membrane should last the stated 6 years easily, since he is within the tolerance range of the manufacturers rating without the water being treated. With the water going thru carbon before getting to the membrane, the traces of chloramines will be a lot lower if not zero.

Okay, thanks. This is good to know. So my membranes are probably still good.

Personally, I would just make changes to what you have. I would go with a 1 micron pre-filter. The zetazorb is most likely overkill. The prefilters will not lower tds, at least not with any significance. You have to realize the ro membrane is rated at .0001 microns. Then I would go with 2 carbon filters. You can do a BRS universal followed by their VOC or do a chloramine specific filter followed by a normal carbon filter. I would then ditch the dual membranes and go with just one. The dow filmtec 100gpd is now rated at 98% rejection so is a good choice or the 75 gal is also good and many seem to get 99% rejection rate with it. Also get a new flow restrictor. You can get the barrel type that you match the part to the gpd rated membrane you are buying. These just plug into the tubing but you can’t adjust them. There is also the capillary style that slides inside the tubing and you trim to change the flow but if you mess up you have to buy a new one. Third option is to buy a valve that allows you to make small changes to the flow. That way you can easily regulate the flow restriction. It all comes down to personal preference.

You are currently seeing ammonia because the chloramine is being broken down by the carbon filter to chlorine and ammonia. The ro membrane does a horrible job at removing ammonia. That is the job of the di filter. In your case it appears the di filter is not working correctly between the ammonia reading and the tds reading. My guesses are it was not packed correctly, the di cartridge was installed upside down (been there, done that), or the media was bad.

The cation media is what will remove the ammonia. I would personally make all the changes above and just go with normal dual di media and see if that works but that is up to you. You can run a canister of cation before the dual di media to make sure it removes the ammonia.

Also ditch the auto shut off kit and add a flush kit that allows you to bypass the di media so you can get rid of tds creep. It is recommended you run the ro unit for a few minutes without running it thru the di media because the tds coming from the membrane will be really high for the first few minutes. It is basically a switch that allows you to switch the product water from the membrane between the waste water line and the di media line.

Thanks @Opus.
Yeah, I imagine the ZetaZorb is overkill. But *if* it actually lasts 5x as long, then the price difference is moot. I have my doubts that it would truly last that long though. It's a pretty big claim.

And yes, whatever I do, I will change to a single membrane. Previously I wanted more water, faster, but now that I'm autofilling a 65g barrel, speed doesn't matter much. I would prefer to not waste so much water though...

I know I packed the DI resin in there really tight! But according to the video from BRS that I referenced earlier, the two DI resins in one doesn't do a very good job of taking out ammonia! So I'm pretty convinced that I need separate ones to be most effective (cation first as you mentioned). Also, my unit does have a flush kit.

But with all this talk of getting a new flow restrictor, one of my TDS meter probes is broken, I need new filters and DI resin anyway, and there's debate on whether I need a new membrane (I agree, probably not), and the idea that I could sell the dual membrane system for a decent amount, I might just go ahead and do the upgrade to a new, better RODI unit with multiple DI stages. The net result is that I shouldn't have to pay much more than just the cost of all the new filters (especially if I were to add DI stages to my existing unit). My RODI unit is over 10 years old now. Even has some rust on top of it. I think it's just time for a new one.

That said, I'm still undecided on which to get. SpectraPure has great support that knows what they're talking about since they specifically work on RODI equipment (while BRS it's hard to say), and it sounds like they make a great product, possibly longer lasting filters, but they're also a lot more expensive to replace. They make great claims, but they're based on their own testing. It would be nice to see some independent testing of the RODI units! Anyway, I'll keep thinking about it and chat with Daniel a bit more. Thanks!
--Kyle

 

[Saltyreef]

I would go through Azdesertrat's posts regarding RODI systems. Hes the unofficial guru across multiple forum sites.

Daniel @ spectrapure is also a wealth of knowledge. You wont be disappointed. Their standard cartridges are refillable and the reason they cost more is because the medias quality is unmatched.

 

[theMeat]

Would this be in relation to my comment of my system?
Im operating at 50-60psi. My concentration is inside spectrapures recommendation at 3x to 5x. If over 6x then there is an issue that would need correction.
I have two extra full size flow restrictors i could trim use to obtain less waste water but at the expense of my filters....
But i dont have an issue with my system it works great right from the box.

Not really sure what your question is. Think my comment was just that spectrapur filter fit on any other standard 3x10 cartridge, and vise /verse
4:1 is ideal for spectrapur. 5:1 will help prolong the life of your membrane but all cartridges that are pre-membrane are filtering more water that ends up as waste as a result

 

[Saltyreef]

Not really sure what your question is. Think my comment was just that spectrapur filter fit on any other standard 3x10 cartridge, and vise /verse
4:1 is ideal for spectrapur. 5:1 will help prolong the life of your membrane but all cartridges that are pre-membrane are filtering more water that ends up as waste as a result

I believe you guys were going back and forth in regards to my waste to product @ 5:1. But i could be mistaken.
Honestly, I gauge my carbon replacement based on my waste water total chlorine level and my prefilter based on an operating pressure range of 50 to 70. No issues thus far with either running 5:1. Im looking to protect my membrane and DI resins. The prefilters are the least of my worry as their the cheapest to replace anyways.

 

[Opus]

@kyley, you may be having high hopes for what you can get for your current system. Maybe you can get what you want for it, I just know around my area they seem to sale fairly cheaply when I see them offered on the local boards and facebook. I see them sale at 1/3 to 1/4 of new cost. My RO unit is a Kent Marine unit that I've had for over 25 years and I've made a lot of changes thru out those years.

You can't go wrong by buying new and then you are getting new seals and tubing also. I've had my tubing crack from becoming brittle.

 

[theMeat]

New tubing is cheap

 

[kyley]

@kyley, you may be having high hopes for what you can get for your current system. Maybe you can get what you want for it, I just know around my area they seem to sale fairly cheaply when I see them offered on the local boards and facebook. I see them sale at 1/3 to 1/4 of new cost. My RO unit is a Kent Marine unit that I've had for over 25 years and I've made a lot of changes thru out those years.

You can't go wrong by buying new and then you are getting new seals and tubing also. I've had my tubing crack from becoming brittle.

True. I don't expect more than half of the new cost. If I get 1/3, that would still help me out pretty well. Being a dual membrane setup, I was thinking I might have more interest / get a bit more for it. But who knows. Thanks,
--Kyle