Two small chloramine filters vs one large one

[Harry Muscle]

I'm doing research on chloramine removing filters and I'm trying to get a better understanding of which setup is better, two smaller filters or one larger one.

For example I've read multiple times that it's a good idea to use two 10" chloramine filters in series. That way when one starts to get depleted and allows some chloramines thru the second filter will kick in. This way you can take advantage of the first filter until it's completely depleted instead of replacing it when it just starts to let chloramine through.

However, the normal 10" chloramine filters have a fairly small capacity compared to the larger 20" or Big Blue filters. For example the standard 10" can filter 1000G at 1gpm, while the Big Blue 10" can filter 3000G at double the flow and probably closer to 8000G at 1gpm. That makes me think that it might be significantly better to go with a single Big Blue 10" filter instead of two smaller filters in series.

However, I'm wondering why I'm not seeing this setup more often. Am I missing something with my reasoning?

Thanks,
Harry

 

[mcarroll]

Which filters are you looking at so far?

A chemical reducer like sodium thiosulfate (AmQuel, Prime, etc) is the best solution to chloramine, but I've never heard of its use outside of batch water treatments.

(Back in the 90's I did research building an in-line NaTh-doser that used powdered reagents, though.)

There's no consistency in RODI setups you see because there is no good, standard, well-agreed-upon way of dealing with chloramines within the RODI system.

On the one hand...

• Activated carbon "works" but has lots of gotchas.
• The membrane "works" but also has issues.
• DI resin also "works" but is a pretty expensive way to handle it.
• (see link at bottom)

And on the other hand, nobody tests their water before, during and/or after chloramine filtration to track the system's effectiveness. Not at all, usually.

So it would be hard for you or I to know which systems are really effective – even when they are.

FWIW, the best way I know is the brass/zinc media ("KDF"?) they've recently been doping carbon with.

Kinetic degradation fluxion media

I don't know if anyone has done any testing at all to see what/if any side effects there are to this media. It seems to be rated for potable water, but not without some questions. It's only been around since the 1980's and only in wide-spread use fairly recently, so it's a largely unknown product by comparison with activated carbon.

If you haven't already bumped into this, check it out:
Chloramine and the Reef Aquarium - Reefkeeping.com

and this, just for nerdly reference:
http://www.isws.illinois.edu/pubdoc/C/ISWSC-53.pdf

KDF makes use of this phenomena, but its inventor (more like discover-er) patented its use in treating water purposefully with it.

At least now I understand why all the valve seats on my house built in 1979 are trashed....thanks, chloramine!

 

[Harry Muscle]

Which filters are you looking at so far?

A chemical reducer like sodium thiosulfate (AmQuel, Prime, etc) is the best solution to chloramine, but I've never heard of its use outside of batch water treatments.

(Back in the 90's I did research building an in-line NaTh-doser that used powdered reagents, though.)

There's no consistency in RODI setups you see because there is no good, standard, well-agreed-upon way of dealing with chloramines within the RODI system.

On the one hand...

• Activated carbon "works" but has lots of gotchas.
• The membrane "works" but also has issues.
• DI resin also "works" but is a pretty expensive way to handle it.
• (see link at bottom)

And on the other hand, nobody tests their water before, during and/or after chloramine filtration to track the system's effectiveness. Not at all, usually.

So it would be hard for you or I to know which systems are really effective – even when they are.

FWIW, the best way I know is the brass/zinc media ("KDF"?) they've recently been doping carbon with.

Kinetic degradation fluxion media

I don't know if anyone has done any testing at all to see what/if any side effects there are to this media. It seems to be rated for potable water, but not without some questions. It's only been around since the 1980's and only in wide-spread use fairly recently, so it's a largely unknown product by comparison with activated carbon.

If you haven't already bumped into this, check it out:
Chloramine and the Reef Aquarium - Reefkeeping.com

and this, just for nerdly reference:
http://www.isws.illinois.edu/pubdoc/C/ISWSC-53.pdf

KDF makes use of this phenomena, but its inventor (more like discover-er) patented its use in treating water purposefully with it.

At least now I understand why all the valve seats on my house built in 1979 are trashed....thanks, chloramine!

Thank you for all that info. I've been looking at the Pentek ChlorPlus filters. They seem to be the best I've found so far for a decent cost. Now I'm trying to figure out whether it makes more sense to do two in series like I see everywhere or one larger one. One larger one seems to make more sense money wise but I don't usually see that kind of setup, just not sure why.

Thanks,
Harry

 

[mcarroll]

I think those are just activated carbon.

Unless I'm mistaken, "catalytic" carbon is simply very activated activated carbon – cooked longer and/or at a higher temperature.

So those may work, but they'll have the same gotchas as activated carbon. #1 being how quick performance goes below acceptable per test results compared to the rated cart. life.

I would be unwilling to pay the extra for those cart's if I wasn't also testing for chlorine to know when to change them.

If you're going to go to that length, then running a dual canister system for the reasons you mentioned can make good sense – assuring total exhaustion of each cart.

Whether one 20" (or fattie) cart could be a better deal is still an open question.....I didn't look up prices for anything. So far as I know, in terms of cost it could be that swapping out plain old GAC in an ordinary 10" refillable canister on a bi-weekly basis could be a better way to go. ;)