Water Filtering and TDS Readings

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Postby mgwolf » Mar 04, 2012, 1:22 pm

I recently plumbed in a Vivaldi (nearly new) and installed an in-line carbon filter (purchased from Chris) with a pressure regulator. I have a central water softener which works well (I tested the hardness). I put the filter in because our local water has lots of stuff dissolved in it (total dissolved solids - TDS) and, in particular, smells of chlorine. I figured the carbon filter would get out a lot of this stuff.

My softened tap water reads 265 TDS going into the machine. After the filter, it goes up to 372 and coming out of the hot water tap of the machine, it reads 565. I'm using the hard plastic water lines that go into John Guest fittings. Are some of the TDS's the carbon leaching from the filter? Can I presume that perhaps the boiler is also leaching metal solids into the water? Is my filter defective? I think my TDS meter is OK since it reads 10-15 consistently from the RO spigot in my kitchen.

Any of you engineers/water specialists care to explain this to me? Thanks.

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Postby MDL » Mar 04, 2012, 1:29 pm

It is necessary to flush the carbon cartridge with lots of water to remove fines prior to connecting the output to the espresso machine (or anything else). TDS measurements are not equivalent to "hardness". I would not worry about TDS but would flush everything (carbon cartridge, boilers, water lines) and then see how things taste. If your hardness is appropriate and the coffee/water tastes OK I would not think about TDS.

Just my personal opinion,

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Postby bravozulu » Mar 04, 2012, 1:41 pm

Flushing newly activated charcoal filters is a must. I worked at two airlines requiring routine changeouts on the carbon canisters in the galleys and rest rooms on 747s. The mechanics would haul along a pail to catch the waste water.

And I believe anyone with tropical fish tanks is well acquainted with the pre-flush procedure.

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Postby Peppersass » Mar 04, 2012, 2:52 pm

Definitely agree about flushing the carbon filter. A warning about that is on the Chris Coffee website page for the filter and is in the instructions that came with the filter. I don't know anything about the internal structure of the Vivaldi, but those little carbon particles can damage or cause havoc with certain machines -- they can get stuck in check valves, gicleurs, etc.

If you didn't flush the filter before you used it, I would flush several gallons through your machine without the filter to try to get that stuff out. Then flush several gallons through the filter into a bucket or drain and hope for the best.

All that said, I'm suspicious about your TDS readings. AFAIK, carbon particles from the filter won't dissolve in water. Is there a run of metal pipe between the point where you've measured the TDS of the water supply and the filter? If so, minerals might be leaching from that pipe. As for the boiler water, I've seen %TDS go up in boiler water due to evaporation, or it could be minerals leaching off the inside surface of the boiler if it's made of copper.

It's conceivable that your softened water is slightly acidic and it's etching minerals off of any metal it comes in contact with. Doesn't seem likely with the high TDS you have (it's not an RO system, is it?) Even so, you might want to get some pH test strips to check that out.

I'm wondering if your TDS meter is working correctly, and if you're using it correctly. For one thing, I believe you're not supposed to measure hot water. You have to let it cool first.
Dick Green

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Postby Randy G. » Mar 04, 2012, 3:08 pm

In terms of scaling, TDS is inaccurate. Softeners replace one mineral with another, so TDS in and out can be roughly the same. Get the Aquarium Pharmaceuticals Hardness GH + KH kit. To get scaling you need levels of both GH + KH. If either is absent, no serious scaling can occur. You can use that to test various faucets around the house to see if the problem is localized or general, and it can test the effectiveness of your softening system.
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Postby mgwolf » Mar 04, 2012, 9:37 pm

Thanks for replies. I did, in fact, flush the carbon filter with several gallons of water before I used it.

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Postby mgwolf » Mar 04, 2012, 9:40 pm

And I let the hot water cool to room temperature before I tested the TDS. I think the Vivaldi boiler is nickel plated, if that makes a difference.

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Postby Javacat » Mar 06, 2012, 2:57 am

Sounds to me that your meter is faulty. If you are simply running a carbon filter then you tds shouldn't change. Carbon filters don't have much of an impact on tds. Their main purpose is to get rid of off flavors. As randy suggested, get some pH test strips at an aquarium store to verify that your water hardness is in the right range (75-90 grains) and I wouldn't worry too much about the overall tds much as it will not do any harm to the machine

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Postby another_jim » Mar 06, 2012, 3:56 pm

A couple of points.

-- Randy us right, softening leaves TDS readings unchanged, you are substituting sodium for calcium.
-- it's a steam boiler, as in steam with no minerals out, and water with minerals in. Stam boilers build up minerals; so the TDS reading is always higher than from the tap water. "Blow down" the boiler occasionally to lower the minerla concentration (run water out of the HW tap to replace the highly mineral water in the boiler with less mineral water from the faucet.

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Postby mgwolf » Mar 06, 2012, 10:15 pm

Thanks for all the comments.

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