Non-RO Water Filtration Showdown

After posting my water report here it's pretty clear that my water is nice and soft and doesn't require an RO system; I just need carbon filtration to get rid of chlorine and chloramine.

Now I'm looking at the available 3-stage water filtration systems and there are some fairly significant differences so I'm looking for feedback.

I'm looking for value (first in recurring costs for replacement filter cartridges and second for initial purchase price) AND the ability to neutralize chlorine / chloramine. (I definitely don't want one that comes with a stupid faucet; this isn't for my home tap water; it's for my brewery!)


Here are a few options that I've found:

1. Watts Premier UF3 http://www.amazon.com/Watts-Premier-531130-Filter-Pure-Filtration/dp/B002XISS2Y/ref=sr_1_fkmr0_3?ie=UTF8&qid=1383162869&sr=8-3-fkmr0&keywords=aquasana+3+stage+water+filter#productDetails $150 (with faucet) Sediment filter, then a carbon block filter, than an ultra fine filter
   Seems like you have to buy their particular (fairly expensive) filters
   # of gallons treated??! -Doesn't seem to say
   
2. iSpring WCC31 http://www.amazon.com/iSpring-WCC31-3-Stage-Undercounter-Filter/dp/B0041LWI72/ref=sr_1_cc_3?s=aps&ie=UTF8&qid=1383162189&sr=1-3-catcorr&keywords=3+stage+water+filtration+carbon+ispring
   $86
   Sediment filter, then GAC carbon, then CTO Carbon
   Appears to take normal 10" filters; twice as much carbon == twice the speed for the same amount of contact time
   
3. Home Brew Filters (unknown brand) http://www.homebrewfilters.com/brew-water-filters/3-stage-water-filter.html
   $90
   5 micron sediment filter, 5 micron carbon block, 1 micron carbon block
   Again, twice the carbon contact time so twice the throughput while still neutralizing chlorine/ chloramine
   Also appears to take normal 10" filters
   
4. Aquasana AQ 5300 http://www.amazon.com/Aquasana-AQ-5300-55-3-Stage-Counter-Brushed/dp/B00CHYLXLW/ref=sr_1_1?ie=UTF8&qid=1383162869&sr=8-1&keywords=aquasana+3+stage+water+filter
   $179
   The price isn't a fair comparison as it comes with a faucet; I need to fine one that doesn't come with the faucet.
   This one is pretty highly rated and the filters last for 600 gallons; it's NSF certified to remove 97% of Chlorine and Chloramine (bonus!)
   They won't say what type of filters but clearly a sediment filter and then what they're calling "Claryum" filters which I assume is a gain a 2 stage carbon setup.
   -The replacement cartridge set is $69 so I'm leaning away from this one.

Both the iSpring and the HomeBrew Filters options seem pretty good; not quite sure of the differences at this point, though.

Anyone have any recommendations on filters for this purpose?


Adam

I know this isn't what you asked- but since you have such nice water and only need chloramine removal, are you against simply using one camden tablet per 20 gallons of water? That would get rid of the chloromine/chorine.

Or do you want the carbon filtration to remove iron or something like that? I'm trying to remember what any issues with your water are, and all I remember really is that I am jealous of your water!

Morebeer has a simple single 10 micron carbon block filter options but I like the idea of using dual back-to-back carbon block filters to increase the contact time and therefore the fill rate at which you can get adequate contact time. I also like the idea of having a nice prefilter to catch any sediment.

I'm curious about the different types of carbon filters that I see and also the different hose sizes; I like that More Beer goes with 3/8th tubing end-to-end.


Adam

I've been using camden tablets for chlorine, but I'm not always going to live where I currently live and I like the simplicity of just running my water in through a filter and having it come out ready for brewing. (I prefer to take out the things that I don't like from my water vs. trying to put more stuff in philosophically, too; yeh, AJ has gotten into my head on this issue.)

I've seen "Granulated carbon filter", "Carbon block filter" (of 1-10 microns), "GAC carbon filters" and "CTO carbon filter". -What the heck are the differences and what should we be looking for in carbon filters for our brewing water?

[Edit it seems that "Granulated carbon filter" and "GAC carbon" are probably the same things; "granulated activated carbon filter".] -But what the heck is the difference between "Block Carbon" and "Granulated Activated Carbon"? Activated and non-activated??



Adam

Ahh!! Pretty much all of these options are "activated carbon"; Carbon Block filters are basically GAC that has been ground into even smaller particle sizes/ a finer mesh; they then have a binding agent added to keep the carbon granules in a static position relative to each other so that they're immobilized and don't allow channeling.

The cheaper activated carbon "GAC" filters generally let some black crud pass through at the beginning while this generally isn't an issue with carbon block filters.
The GAC filters can also allow bacterial growth inside the filter. Carbon block filter pore size can be controlled to a small enough size to almost eliminate bacterial growth inside the filter.

"Carbon Block" == "Higher quality GAC".

Even within carbon block filters there's then 2 manufacturing techniques: compression and extrusion. Compression is more labor intense and expensive but results in a more consistent matrix and requires less binder material.

SOOO, it sounds like if I'm going to bother with this I want a double carbon block filter; possibly with a larger micron rating for the 1st one and a smaller micron rating for the second one to maintain throughput.

Hmm.. GAC filters allow a much faster flow rate through them but provide little contact time so this is why you often see GAC used as the 1st stage and then a compressed carbon block second -interesting...

The NSF rated ones essentially come with a basic guarantee of performance, too. NSF standard 42 for reduction of chlorine and asthetic issues and Standard 53 for lead and aresenic reduction.

Hmm... If I can't find what I want I'll find a 3 x 10" housing and just build my own... (Considering 3 stage GAC -> 5 micron carbon block -> 1 micron carbon block.)
I did NOT think this would be this complicated of a discussion; pretty cool, though.

Adam

The HomeBrewFilters.com option is looking better and better.

The first carbon filter is block carbon at 5 micron and the second is a 1 micron block carbon filter. The size of the tubing is my only concern right now...
-His filters are extruded and not compressed but I can't find any compressed ones that come in a standard 10" (technically 9.75") size that are reasonably priced right now....

Adam

OK!! You are a frenetic writer! Good to see so much vigor.

There is no need to concern yourself with a pore size rating for the carbon block media. The most important thing is that your initial particulate filters have sufficient selectivity to protect the downstream carbon units. Particulate filters are cheap, carbon is not. If the water has that much particulate sediment, then a dual particulate filter may be called for. Start with a 5 or 10 micron filter followed with a 1 micron filter. Follow those particulate filters with a carbon block with a pore size rating LARGER than the minimum particulate pore size rating. This will keep fines from clogging up your expensive carbon filter. Those very fine particles will just pass through. It is not a big deal.

There are activated carbons that have been optimized for chloramine oxidation. However, the bottom line remains that the residence time in contact with the carbon must be long enough to obtain full removal of the chloramine. Since other taste and odor components in water also require a long contact time, there really isn't a short-cut to producing quality water from a carbon filtration system. Low flow rate is a requirement. Of course you can read more about AC filtration on the Water Knowledge page of the Bru'n Water site.

Thanks again, folks!

Martin, I am pretty famous(infamous) for writing a lot; part of the reason is that I process information externally and have to type it or say it out loud to fully understand it; the other part of it is that I'm really impatient and won't wait for an answer. -I'll try to go and find it instead.


Adam

Brandon from homebrewfilters.com sent me a great reply on carbon filters and chloramine reduction so I'm going to share it. Normal carbon filters only break the ammonia-chlorine bond in chloramine and then absorb the chlorine but pass the ammonia through to your water. Catalytic surface activated carbon (available as loose fill "gac" or carbon block) further breaks down the ammonia -this is how the chloramine treating filters work, apparently.


Adam

For what it's worth I contacted the Seattle Public Utilities and they let me know that Seattle is still only chlorinating, not chloraminating the water here so normal, cheaper carbon block filters will work just fine. Woot!


Adam

biertourist said:

Brandon from homebrewfilters.com sent me a great reply on carbon filters and chloramine reduction so I'm going to share it. Normal carbon filters only break the ammonia-chlorine bond in chloramine and then absorb the chlorine but pass the ammonia through to your water. Catalytic surface activated carbon (available as loose fill "gac" or carbon block) further breaks down the ammonia -this is how the chloramine treating filters work, apparently.

Click to expand...

In the typical application the overall reaction is

3NH2Cl -->2H+ + 3Cl- + N2 + NH4+

Note that the carbon is not, theoretically, consumed in this reaction. The released ammonium ion is considered a benefit as it is a yeast nutrient (brewers often add diammonium phosphate as a nutrient to starters and brews).

Given that the municipal water is not chloraminated it is not necessary to filter or treat with metabite or thiosulfate as chlorine is quite volatile and will leave the water without treatment if the water is allowed to stand for a few hours especially if it is heated and aerated. When you can't smell chlorine any more it is sufficiently dissipated (unless you are one of those who cannot smell chlorine).

The only reason GAC filtration works to break down ammonia is that it has a tremendous amount of surface area to grow nitrogen fixing bacteria. Typically these are species of nitrosomonas sp. bacteria that convert the ammonia into nitrite. Nitrobactir can then grow and convert the nitrite into nitrate, which is non-toxic and the end product of biological filtration.

The absorption/adsorption power of GAC and carbon block filters is also finite. There is only so much material the carbon can store before it hits saturation and will begin leaching compounds back into the product water. Remember that you will have to replace the carbon block filters every few months (six months to twelve months depending on source water) and the paper micron filters more often. I agree with the previous suggestions to go with a larger paper pre-filter (50 micron or so) and then a finer pre-filter (10 microns) before the water reaches the carbon post filter. These will clog up with debris first and need replacing more often. The more clogged the pre-filters get, actually the better they will work. You could even use diatomaceous earth in your 50 micron filter to reduce filtration to 1 micron and really polish the water clean.

Do you want to know what many big commercial breweries use to filter their water? They use a system that was originally developed to create lab grade water for dialysis equipment which uses a ceramic media developed by polybiomarine. There is a home system that produces highly pure lab grade water called the Kold Steril unit. The advantages of this system is not only are all of the media inexpensive or rechargeable, but none of the water is wasted in comparison to reverse osmosis units. You can push water through at normal household water pressures (30 psi) and have pure product water come out the other end.

The water filtration unit that I like to use for aquarium water also produces no waste water. It's called the Kent Marine Deion 200R unit. It consists of a paper micron/carbon post combo, a cation adsorbing media and an anion adsorbing media. The two chemical medias remove over 99.5% of all TDS (total dissolved solids) and also produce no wastewater. The media can be recharged with a muriatic acid rinse and lasts forever. You can also push regular household pressure water through it and it produces up to 200 gallons a day of pure, clean product water. So pure, you have to add magnesium salts back to the water to make it pH stable and the water potable (drinkable).

Aiptasia, You seem to have experience with filters. Maybe you can explain how my 8 yr old KX Pb filter was still filtering chloramine when I replaced it.

My old filter had reasonably good flow and the water tasted good. When I ordered the replacement I asked about chloramine. She replied ‘good question, how ‘bout I send you some test strips and you let me know?’

The indication from the strips was that I had 3 ppm total chlorine coming in, but the test strips looked identical for the filtered water with the old filter, the new filter, RO water and distilled. The lowest indication on the color chart was .1 ppm.

It seems to me that carbon block at 1 micron is way better at filtering chloramine than the literature suggests and that chloramine is WAY less of a problem than free chlorine.

Aiptasia, your explanation of how activated carbon destructs chloramine differs from the engineering texts on water treatment that I have. It also differs from the explanation I had from my engineering professor at UF in the class on activated carbon treatment that I took a few years ago. All those sources indicate that the carbon is actually oxidized by the contact with either hypochlorite (aka: chlorine) or chloramines.

While you clearly are familiar with the nitrifying performance of bacteria, I don't think that would be the primary mechanism for nitrogen removal in an AC bed. That would be apparent with new AC filter media, since the population of bacteria would not be present and the dechlorination mechanism still works.

You are correct that the dechlorination capacity of AC is finite. However, it is more likely due to the consumption (oxidation) of the carbon mass and the shielding that the oxidized material provides which prevents subsequent chlorinated compounds from contacting the remaining carbon. It does not appear that the exhaustion of adsorption sites is the mechanism that exhausts AC capacity for chlorine. Since adsorption is not the mechanism employed in AC for chlorinated compound removal, it does not suffer the leaching mechanism that is a problem for AC that adsorps contaminants. If you detect chlorine compounds after AC treatment, its because the flow rate is too high or the AC is exhausted and there is breakthrough of the chlorine compound, not leaching.

The polybiomarine media sounds interesting since you mention it is a ceramic. However, this sounds just like the function of typical deionizing systems in which there is are cationic and anionic beds of resin beads that provide the deionization. Strong acid or base are used to regenerate those resins. The Kent unit that you describe is that sort. I think you mis-spoke regarding the use of muriatic acid for the anionic unit, that will not supply the OH- ions needed to recharge the anionic resin. I have not heard of breweries using this type of demineralization since membrane processes such as RO or nanofiltration are more economical in large scale. I think that most homebrewers would find that deionizing via this method is also a bit more expensive than a membrane process.

aiptasia said:

The only reason GAC filtration works to break down ammonia is that it has a tremendous amount of surface area to grow nitrogen fixing bacteria.

Click to expand...

The explanation given by texts like Faust and Aly is that an activated site which has been oxidized by one chloramine molecule

C* + NH2Cl + H2O --> H+ + Cl- + NH3

is then reduced by another

C*O + 2NH2Cl -->C* + 2H+ + 2Cl- + H2O + N2

with C* representing an active carbon. This model was reiterated in a talk on activated carbon in the brewery I attended last week. Thus, as I indicated in my earlier post, ammonia is not broken down and this is, in brewing, a good thing and is a consequence of the lower pH range typical of brewing. In the aquarium hobby and dialysis systems it is not. Also, as mentioned above, theoreticlly, the carbon should last forever or if it doesn't it isn't because it loads up as a consequence of removing chloramine. Chlorine is a different matter. The carbon is consumed.