Reverse osmosis system, which one and is chloramine removal necessary?

[renthispace]

I'm in the market for a RO system and have been doing my homework. I've read the thread https://www.homebrewtalk.com/f11/inexpensive-but-good-reverse-osmosis-system-312102/ and get that a Dow RO membrane is preferable (potentially less waste water) than cheap no name ones.

I would love to spend ~$100, but as always sometimes it's better to spend more to get more. Most of the cheap units utilize the small filter housings. While I will only be using this RO filter for beer and it will not have a large volume of water through it, obviously there will be a time for replacing the filters. I would imagine that the units with larger filter housings (while more expensive initially) would last longer and have cheaper replacement parts as they are more universal.

My biggest issue is that I realize that my water is treated with chloramine---which is difficult to remove but possible with carbon. Some system sell a 'catalytic' activated carbon filter to really scrub that chloramine out of the water. Of course that is more costly than normal RO systems., which already have carbon filters.

So is the catalytic carbon worth it? Should I just continue my use of campden tablets with RO water and not worry about the chloramine? Will the carbon filters in regular RO systems be enough for the chloramine and the catalytic carbon thing is just marketing hype?

And really, the only way to know when filters need replacing is with testing the treated water. When the TDS starts to rise, replace the RO membrane. When the free chlorine starts to rise, replace the carbon filters. So now I just need to get a pH meter, free chlorine tester, and a TDS meter in addition to my RO system.

Here is a good link on chloramine and RO systems: http://www.reefkeeping.com/issues/2003-11/rhf/feature/


And these are the RO systems I am considering:

Small filter cartridges
$70-100 (depending on flow rate) http://www.marinedepot.com/AquaticL...Systems-AquaticLife-AK010161-FIROROTS-vi.html
$90 http://www.bulkreefsupply.com/brs-3-stage-space-saver-ro-system-75gpd.html

Large filter cartridges
$130 http://www.bulkreefsupply.com/brs-4-stage-value-ro-di-system-75gpd.html
$200 with chloramine filtration http://www.bulkreefsupply.com/brs-5-stage-chloramines-ro-di-system-75gpd.html
$130 and optional $17 for chloramine filtration http://thefilterguys.biz/ro_di_systems.htm


Any suggestions, thoughts or comments? I know I don't need DI but the chloramine thing is bugging me.

 

[dyqik]

I'd say just stick to Campden tablets for the chloramine. $17 will buy several years worth of Campden tabs, which will outlive the more expensive filters.

 

[WPStrassburg]

Give Buckeye a call and they can tailor a system for you.
http://www.buckeyefieldsupply.com/showproducts.asp?Category=164&Sub=103

BRS is a good option too and may be able to customize a unit for you.

I bought the cheapest unit off ebay with a Dow/Filmtec membrane I could get since the pre filtration didn't make much of a difference for me. The membrane and specialty filters are the things that should drive the cost on these and not the brand so shop smart and save yourself a few bucks.

 

[photogscott]

Does the water taste bad for drinking? If not then do what many breweries do... nothing

 

[Epimetheus]

My biggest issue is that I realize that my water is treated with chloramine---which is difficult to remove but possible with carbon. ...

So is the catalytic carbon worth it? Should I just continue my use of campden tablets with RO water and not worry about the chloramine? Will the carbon filters in regular RO systems be enough for the chloramine and the catalytic carbon thing is just marketing hype?

Like dyqik said, I would simply use campden tabs because they are simple. Chloramine is much more stable than free chlorine. (Well, darn near anything is less reactive than chlorine ions.)

Chloramine is often the stuff in pools that stings your eyes. Some people think their eyes hurt because too much chlorine was added. It is usually the chloramine which forms after the chlorine ions have done their job and are bound to nitrogen from organic sources (sweat, urine). This as amateur knowledge, I maintained our above-ground pool for 8 years and got into the chemistry of it. The campden tabs (sodium or potassium metabisulphate) reduces the chloramine and gives just one electron to the chlorine atom so it is not so reactive. Then it is a chloride and just sits there and minds its own business.

 

[Ramitt]

Does the water taste bad for drinking? If not then do what many breweries do... nothing

Theydo if there are chloramine, that stuff ruins beer.

 

[Buckeye_Hydro]

a Dow RO membrane is preferable (potentially less waste water) than cheap no name ones.

Dow makes membranes under the Filmtec brand name. These are widely considered the best membranes available, and many other membrane manufacturers but their flatsheet from Filmtec, and then "roll their own."

Filmtec membranes are factory spec'ed at 50 psi, where other brands are spec'ed at 60 or even 65 psi.

Given all that, you can control the ratio of waste water (aka "concentrate") to purified water (aka "permeate") on any RO system with a little $4 part called a flow restrictor. Every RO system has one.

I would love to spend ~$100, but as always sometimes it's better to spend more to get more. Most of the cheap units utilize the small filter housings. While I will only be using this RO filter for beer and it will not have a large volume of water through it, obviously there will be a time for replacing the filters. I would imagine that the units with larger filter housings (while more expensive initially) would last longer and have cheaper replacement parts as they are more universal.

So true. There are 4 different "standard" size filters:
10" long x 2.5" diameter
20" x 2.5"
10" x 4.5"
20" x 4.5"

The housings made for 10" x 2.5" are what 99% of people would consider standard, and may be all you've ever seen. If you go to a hardware store that's all they'll have.

If you go with smaller inline filters the original cost of the system will be low, but over time you'll spend more on replacements. We've never made/sold the mini systems and I doubt we ever will. We've got to sleep at night!

My biggest issue is that I realize that my water is treated with chloramine---which is difficult to remove but possible with carbon. Some system sell a 'catalytic' activated carbon filter to really scrub that chloramine out of the water. Of course that is more costly than normal RO systems, which already have carbon filters.

So is the catalytic carbon worth it? Should I just continue my use of campden tablets with RO water and not worry about the chloramine? Will the carbon filters in regular RO systems be enough for the chloramine and the catalytic carbon thing is just marketing hype?

Chloramine is a mixture of chlorine and ammonia. Realize that what the carbon does is break this bond. The chlorine or chloride is handled by the carbon and membrane. The ammonia goes through the membrane in large part. If present as ammonium the membrane will deal with it.

The thing is that chloramine requires longer contact time with the carbon than does chlorine. So adding a second carbon stage may not be absolutely necessary in all situations, but it is good inexpensive insurance. On good systems intended for use with chloraminated feedwater you'll see CGAC filters or special carbon blocks. These filters use a special type of carbon that does its work faster than a typical carbon block. Cartridges containing standard, old-fashioned GAC should be avoided - there are much better options available.

Russ