After a few google results, I am a bit confused (imagine that). I know a carbon filter is one way to remove chlorine from tap water, but what else does it remove? Calcium, magnesium, sodium, chloride, sulfate, …?
That depends on the filter and how fast you run your water through it.
Mostly just chlorine and sediment. It’s not effective at removing dissolved minerals. And yes, the water has to be run slowly to remove the bulk of the chlorine.
I find that using an inexpensive, standard sediment filter before the more costly carbon/chlorine filter gets you better performance and longer life from the carbon filter. Let the cheap filter take out the sediment.
Thx all!
Carbon filters remove many things, but not the ions we are concerned with in brewing.
This covers what is removed and not removed.
What I’ve read is 1 gal./min. for chlorine and .1 gal./min. for chloramine
Slow and Real slow.
Assuming I need 8 gallons of water which has chloramine. It takes 10 minutes to get one gallon through a carbon filter, so that means 80 minutes for 8 gallons. Is this correct? I always understood it had to be slow, but wow.
I will continue to add a half Campden tablet after I run it through the filter.
i used to buy very cheap high strength soju (3.6L jar at 35%ABV for ~8 bucks) and i tried making it run through a carbon filter setup. it was incredibly slow. like drip… drip… slow. it did not work how i imagined it would.
Yes, that is correct
Those are flow rates through a standard 2.5" diameter, 10" long filter unit. The flow can increase if your using larger filters or multiple filters.
The real problem is that water can flow through that standard filter unit at around 4 to 5 gal/min and that is FAR too high to remove anything completely…and you do need to remove ALL chlorine compounds or you will leave enough in the water to create chlorophenols in your beer.
I have two total house filters daisy chained together. I flush it first every time then start the run very slow and come back to get the water later. It tests negative for chlorine – assuming those test strips are accurate
The liquid test kits sold for swimming pool chlorine level are probably more accurate and longer-lived than test strips. It is very wise that you’re testing your output to confirm that your filter is doing its job.
Martin calling me wise just made my day! ;D
I always hesitated to use those strips due to accuracy concerns. Great tip on using the liquid test kits. A quick search on-line shows them to cost around $15-20. It seems prudent to use those to verify my procedure is working sufficiently.
I guess the strips are better than nothing. That is all I ever used after I saw a water tech guy use them at my brewery to test the water after he installed the filter. They definitely have a limited shelf life though IME that seems to be shorter than their exp date. The ones I bought last year worked at first and then turned off white-yellow and don’t read anything now.
We used these strips where I worked and I use them at home: Amazon.com
They are EPA-approved for compliance monitoring and have a 5-yr shelf life. I have no reason to doubt their efficacy. They only work for chlorine, though, not chloramine.
Re: pool water test kits…these are intended for free chlorine, because that’s what’s used in pools. Do they test for chloramine? I have no idea. Would be a bummer to get a false negative because the test doesn’t work for chloramine.
There are two types of filter media… GAC (granular activated carbon) and Carbon block. You want the latter for best performance removing chlorine and chloramine especially at higher flow rates.