I finally broke down and purchased a small 4-stage RO unit, so that I could build water from scratch. I was fairly disappointed with the results that I received when I ran hardness and alkalinity tests against the water produced by this filter. The filter left 42ppm hardness and 24ppm alkalinity in the water, and my water is not super hard or extremely alkaline before it enters the filter. That’s not the reduction that I was expecting. Is there a break-in period for RO filters?
Check out aquarium forums. They have tons of info on RO systems.
Mark, I bought a 4 stage under the counter system last spring. I’ve been very happy with it. It’s very slow, but I can work with that. I sent two samples to Ward and got the following results. My water’s TDS is 262 ppm, after treatment it is 24 ppm, hardness is 204 ppm, after treatment it is 7 ppm and the alkalinity is 227, after treatment it is 6 ppm. My waste goes on my lawn/hops or hay field in the winter.
I don’t remember but I believe they wanted to discard the first batch (3 gallons). Good to go after that.
I would give them a call, something seems wrong.
Bruce
You should be seeing at least 95% reduction in the total dissolved solids. Some of the ions are removed at a higher rate, so the overall performance should be 95 or higher.
There is a very slight break in period, like you’re supposed to run water through the filter constantly for 30 or so minutes after replacing filters. Either something is up with your filters or they’re just not good filters. I got my TDS down to 4ppm with mine.
I do not own a TDS meter at the present time, but I do own Hanna HI775 Fresh Water Alkalinity, HI721 Iron, and HI709 High Range Manganese HC colorimeters and a Hanna titration kit for combined hardness. It appears that Hanna has finally released a fresh water version of their marine calcium hardness HC colorimeter as well as fresh water HC colorimeters for magnesium hardness and chloride. I asked for a fresh water version of their calcium hardness meter two years ago. Now, all we need is for Hanna to release a sulfate colorimeter. :) Most brewers could get away with the HI719 Fresh Water Magnesium Hardness, HI720 Fresh Water Calcium Hardness, the HI775 Freshwater Alkalinity colorimeters.
By the way, the Hanna colorimeters are very accurate for being relatively inexpensive devices (Hanna gets you on the reagents kind of like razors and razor blades). We recently had our water tested for a whole slew of non-brewing related compounds and organisms by a local analytical lab. The results that came back where in line with the results from the colorimeters.
How high is the tap water TDS? 4 ppm is darned good!
I’m probably pretty lucky in that regard, but I think I recall my tap water being 160ppm or something like that. Not crazy high.
Last I checked, the TDS was 7ppm after almost 6 months of running only brewing water through my RO system. So, still going pretty good.
When I use mine, the first slug of water out the faucet has a higher PPM than you would expect. After a few seconds, I measure again and it is back down where you would expect.
If it is not getting where you expect after running for a minute or two then yeah, something is not operating correctly.
I think something isn’t right. I have hard water, but not extreme. Here is my tap water report from Ward labs followed by my RO water:
Total Dissolved Solids (TDS) Est, ppm 179
Electrical Conductivity, mmho/cm 0.30
Cations / Anions, me/L 2.9 / 3.2
ppm
Sodium, Na 40
Potassium, K 5
Calcium, Ca 12
Magnesium, Mg 5
Total Hardness, CaCO3 51
Nitrate, NO3-N 0.2 (SAFE)
Sulfate, SO4-S 3
Chloride, Cl 6
Carbonate, CO3 9
Bicarbonate, HCO3 154
Total Alkalinity, CaCO3 141
Fluoride, F 0.53
Total Iron, Fe < 0.01
“<” - Not Detected / Below Detection Limit
And here is the same report out of my under-the-sink Culligan RO system:
pH 6.5
Total Dissolved Solids (TDS) Est, ppm 8
Electrical Conductivity, mmho/cm 0.01
Cations / Anions, me/L < 0.1 / < 0.1
ppm
Sodium, Na < 1
Potassium, K < 1
Calcium, Ca 1
Magnesium, Mg < 1
Total Hardness, CaCO3 3
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S < 1
Chloride, Cl < 1
Carbonate, CO3 < 1.0
Bicarbonate, HCO3 < 1
Total Alkalinity, CaCO3 < 1
Total Phosphorus, P 0.09
Total Iron, Fe < 0.01
“<” - Not Detected / Below Detection Limit
Steve, excepting for the alkalinity, that tap water is already fine for brewing. No RO needed. A little acid was all you needed. However, it is nice to have a clean slate for some styles.
Good to know. The main reason I decided to brew with RO was that the water source changes during the year. That and I’m just too OCD for my own good sometimes.
fixed that for you.
mark - what model did you buy?
The RO filter is four-stage low-cost model from Pure Water Club. It has a TFC RO filter. The good news is that the lower cost RO filters apparently do have a break-in period. I retested this evening after running the filter for 30 minutes and then collecting 6 gallons of RO water. There was a significant reduction in hardness and alkalinity between this evening’s readings the first set that I took the other day.
It sounds like the unit just needed to be rinsed (1-2 cycles).
An RO system should produce water of 30-40 uS/cm or less. An EC and/or TDS tester should be used to periodically check the system performance. The problem with RO is that it is possible to get a tear in the membrane and not know it. The only way is to check with a tester. Ideally a EC tester with a 0 to 99 uS/cm range (0-50 ppm TDS). The reason being is that many testers have 2% full scale accuracy. A meter with 0 -1999 uS/cm will have an accuracy of +/- 40 uS/cm while the 0 to 99 uS/cm tester will have a +/-2 uS/cm accuracy. I have measured RO water with a a tester that had a 0 - 3999 uS/cm range. It seemed to measure okay with a reading of around 40 uS/cm but technically the reading obtained could be from -40 to 120 uS/cm since the accuracy is +/-80 uS/cm.
Lake Michigan Frankfort Groundwater GW after softener Softened GW after RO
pH 7.2 7 7.3 5.8
EC (uS/cm) 308 990 1190 37
Alkalinity(ppm) 180 870 630 50
Hardness (ppm) 150 720 60 0
I would be curious if sulfate is an important parameter. In principle it would be relatively easy to offer a sulfate checker since there is a sulfate portable (HI96751). If there is a need in the market then it would make sense to offer.
Where is Frankfort? No way do I want their water.
South Suburb of Chicago. Relatively hard water, there are places worse off. I am sure some people from Texas can state to that. Overall the water is not that bad. Just needs to be softened and use RO for drinking water.
That is super hard and alkaline. Far more than TX water analysis that I have seen.
I don’t have a full analysis on my water, but I know the TDS is about 250ppm out of the tap. The RO machine I buy my water from is normally around 10ppm, and I won’t buy from it at 20ppm or higher. Luckily most of the grocery stores here have RO machines out front, but my preferred machine pours 25% heavy and is priced at $0.25.