Mavea Efficacy

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
JohnW
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#1: Post by JohnW »

I installed the Mavea c-50 last January to take care of the very hard (24 grains) water I have feeding my (then) new espresso machine. I have the bypass set to zero because I was very worried about scaling and I use a very small amount of water for my espresso needs. I run the water through a flow meter which indicated I have used only 20 gal. of water in the last 7-8 months. I decided to check up on my water hardness last week and discovered my hardness level going into my machine is now reading 16 grains. Seems very high after just 20 gals. of flow-through and a zero bypass setting. Chris' Coffee has advised me to replace the filter, which I will be doing.

Here are my questions -
1. Does this seem reasonable that the c-50 filter has reached the end of its usefull life after filtering just 20 gal. (maybe less) of water?
2. Should I be using a different filter system, or can I feel comfortable with staying with the Mavea, using the c-150 this time for the replacement?

Any advice you can give me would be most appreciated.

John

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homeburrero
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#2: Post by homeburrero »

Zero replies in 3 days - looks like a tough question.

I can't say I know the answer. Looking at the specs on the C-50 and doing the math, it looks like it has about a 1500 grain capacity*, and therefore at your 24 gpg should handle around 60 gallons at zero bypass.

It may help to say exactly what type of hardness you are measuring. And Mavea tends to cloud the issue. If you are using Mavea's "temporary hardness" or their "carbonate hardness" test kit be aware that you are actually measuring alkalinity, which happens to be roughly the same as actual temporary/carbonate hardness if the total hardness is greater than the alkalinity, which is usually the case in natural waters.

it's often best to know the total hardness (GH) as well as the alkalinity (most test kits call it KH) when looking at softeners. A decarbonizing softener (which the C-50 is) should tend to decrease the GH and the KH by equal amounts. If one or the other is unusually low that would impact effectiveness.

* Spec sheet says it handles 254 US gallons of 10 gpg water at the 40% bypass, and 0.60 * 254 gal * 10 grains/gallon = 1524 grains
Pat
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JohnW (original poster)
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#3: Post by JohnW (original poster) replying to homeburrero »

Thanks so much for the reply, Pat. I checked-in looking for a reply pretty regularly for those 3 days and guess I sort of gave up. Really glad I checked back in - you really sound like you know what you're talking about.

So, to cut right to it I do have some questions:
1. Should I get a test kit that will test GH? I've been using the Mavea Carbonate Hardness Test Kit.
2. I've stopped using the Izzo Leva since I discovered the hardness with the test kit (paranoid of scale build up). Am I correct in thinking the test kit is showing me something to be worried about (14 grains)?
3. Do you think the Mavea is going to cut it, or should I be looking at something else, e.g., BWT or RO?

John

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homeburrero
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#4: Post by homeburrero »

JohnW wrote:1. Should I get a test kit that will test GH? I've been using the Mavea Carbonate Hardness Test Kit.
Yes, I think so. Estimating whether and how much scale might accumulate in a machine requires at a minimum both the alkalinity (what that Mavea test kit, as well as other KH test kits measure) and the GH. The bible for understanding how that works and the formulas and tables you can use is Jim Schulman's Insanely Long Water FAQ -- get it here. It's an alt.coffee post maybe 20 years old but still the best thing out there for understanding this stuff.

When evaluating a softening filter's effectiveness it's best to look at the before and after GH numbers. There are two basic types of cation exchange resins, and both work to reduce the GH. Conventional softeners replace calcium and magnesium (GH minerals) with either sodium or potassium. Decarbonizing filters like the C50 replace the sodium and magnesium with hydrogen ions which are then buffered by carbonates to produce water and CO2, so these reduce the KH as well as the GH.
JohnW wrote: Am I correct in thinking the test kit is showing me something to be worried about (14 grains)?
If your GH is also high, that might drop a lot of scale. Scale is less of a worry than corrosion, though. You can generally deal with scale by periodic descaling (although if both GH and KH are up in that 14 grain range, you'd need go descale every 30 liters or less of thruput.) There are conditions where 14 grains of KH would not cause scale at all. For example, say your hard water was already treated by a whole house conventional softener before getting to that Mavea filter. In that case you would end up with very high alkalinity (would test very high using that Mavea test kit) and very low hardness and it would not deposit scale.
JohnW wrote:3. Do you think the Mavea is going to cut it, or should I be looking at something else, e.g., BWT or RO?
I don't think going to a BWT would help -- is the same type of softener (decarbonizing filter, with WAC resin.) And you you need to know more about your water before deciding to go with RO. Besides knowing the GH and the KH, it's often good to know the levels of chloride ion. Also silica if your water comes from volcanic sources. If either of those is very high you have good reason to go with RO irrespective of scale issues.
Pat
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JohnW (original poster)
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#5: Post by JohnW (original poster) »

Thanks a million for all your help, Pat. I really do appreciate it. Can you suggest a good test kit for the stuff you said i should look for in my water?

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homeburrero
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#6: Post by homeburrero »

Hach ( https://www.hach.com/single-parameter-t ... 5547009716 ) makes the best simple drop count titration kits, and has by far the best technical discussions, but is more expensive than the popular kit used by aquarium people. For total hardness and alkalinity the API GH & KH kit is inexpensive and easy - https://www.amazon.com/API-TEST-Freshwa ... B003SNCHMA

Hach has a drop titration kit for chloride, but you're probably better of checking into that by searching or contacting your water utility for those numbers. Same with silica.
Pat
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JohnW (original poster)
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#7: Post by JohnW (original poster) replying to homeburrero »

This is great, Pat. Thanks.

(Sorry for my ignorance, but what is "drop count titration"?)

Now I just need to decide which test(s) I should use to analyze my water. Btw, we use well water here - no water utility involved.

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homeburrero
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#8: Post by homeburrero »

Drop count titration is a method where you add a reagent one drop at a time, and watch for a color change, counting the drops. Then you use a table to convert the number of drops to a measurement of degrees, gpg, mg/L or whatever. It's a step up from a test strip - better accuracy and precision and a little more complicated to perform, but still very easily done and good enough for our purposes.

Since you are on well water, If you don't have a lot of road salt use in your area, and are not somewhere where salt water incursion is likely you can skip the test for chloride. Having your water tested is a good option for people on wells. Let them know you want to know the hardness and alkalinity, and that you are also interested in chloride and silica if those numbers run high (over 30 mg/L) in your area.
Pat
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JohnW (original poster)
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#9: Post by JohnW (original poster) »

homeburrero wrote:
Since you are on well water, If you don't have a lot of road salt use in your area, and are not somewhere where salt water incursion is likely you can skip the test for chloride. Having your water tested is a good option for people on wells. Let them know you want to know the hardness and alkalinity, and that you are also interested in chloride and silica if those numbers run high (over 30 mg/L) in your area.
We don't have a road salt issue here (Charleston, SC), but there may be chloride in the water as we are in the "low country" and brackish water is present during high tides in the river that is just 1/4 mile from my property. I think I should just go ahead and try to find someone to test the water for the things you mentioned and go from there. I may be back in touch for a good solution once I know what is in there.

Thanks a bunch.

John

JohnW (original poster)
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#10: Post by JohnW (original poster) »

Just had a water treatment salesperson out here to test my water and propose a solution. Here are the results:

Brackish water! No wonder I have serious problems with my espresso machines.

As reported - ph 8.5
Hardness 3 gpg
Iron .1 ppm
TDS 977 ppm (Total Disolved Solids)
Heavy Metals 75 ppb
Chlorine 0
H2S ND

The proposed treatment unit is a reverse osmosis system (ERO 375) by ECOWATER (https://www.ecowater.com/home-water-sol ... r-systems/). It would be installed under the kitchen sink to serve drinking (cold) water only via a dedicated faucet at the sink, and a dedicated water line to my Alex Leva.

According to the salesman, my ro treated water would should have about TDS of 150-210 ppm, a ph of 8 - 8.1, 0 gpg of hardness, 0 iron and less than 20 ppb heavy metals.

Should I find a way to get the TDS lower?

I've done my best to accurately pass along the data as it was reported to me. Given that I don't really understand the chemistry, there could be errors in the way I have presented the data.

Pat, I would love to hear your response and assessment of the proposed solution. Thanks in advance for your input. John

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