Hard water with very low pH? - The Planted Tank Forum
 
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post #1 of 12 (permalink) Old 08-15-2018, 12:37 PM Thread Starter
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Question Hard water with very low pH?

What can make water look hard while not testing as hard?

When tested with the API GH test kit it is less then 1 degree hardness.

The water leaves these white minerals everywhere, which eventually build up on pipes and hoses, especially the hot water. Leaves white crap all over the dishes. It also leeches metal from brass fittings and causes then to crack and leak.

Recently I suspect is was responsible for ruining an RO membrane which dropped down to 50% efficiency within a few months of light use.

It is well water and the pH is 4.5 consistently. TDS is around 100.

Attached image is a hose that is caked with these mineral deposits. Mostly white with a little rust coloration.


- Is it possible there is something else in the water that is giving an inaccurate reading on the test, the pH for instance?

- What kind of test is more precise that can tell me what minerals these are?

- Also, is the low pH a result of these minerals, or is that a separate issue entirely?

- Should we get a softener or a neutralizer, or both?

Main issue is that I cant keep buying RO membranes every few months when they are supposed to last a year o r more.

Thanks!

https://imgur.com/ur4dCkJ

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post #2 of 12 (permalink) Old 08-15-2018, 02:06 PM
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What RO system are you using? I'd make sure you're using a quality sediment filter and a quality carbon block. Carbon, for well, might be less important unless there is contamination potential, so maybe run dual sediment, skip carbon?? Do something like a 0.1 sedminet filter for #1, followed by either another 0.1 or a 0.5. While carbon will filter out chemical contams and then things like jardia, the main purpose for me is that it removes chlorine. Chlorine will destroy an RO membrane real quick.

Is your GH test in date? Have you let water sit for 24 hours and then test pH?

I'm not sure what mineral would come through in such amounts while not affecting GH...where do you live? That could help narrow things down potentially.
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post #3 of 12 (permalink) Old 08-15-2018, 02:33 PM
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I am very familiar with the mineral deposits from calcium and that does not look like what I would expect so moving to other s that might make a white deposit, I might suspect the water is from near a salt dome. Somewhat random guess, there without more info but salt does make water soft and the domes can occur pretty much anywhere without many people knowing about them. Think of the way magma can bulge up through the crust above and then think that salt can form in much the same shape? You can see that one might have a well which is drilled down near this dome, while a well only a mile away might draw water from a totally different environment.
I might suggest taking advantage of some of the free services to get a better idea of what the water has. Perhaps, an easy way would be trying the softener companies free tests, that I see hanging in places like Lowe's, Home Depot. , etc. Do not automatically take those answers as a final as they do tend to recommend softeners. However, before going with softeners, I would want to have a less biased opinion so might look to some of the government services. There are often county or ag services that will test and give a much better/more complete set of data.
Keep in mind that much of this is from what I have experienced and lacking any real test results. PH of 4.5 is pretty extreme and not something I have found occurring naturally so there may be some pollution source involved and I would want to have it tested before using it for many things, especially cooking and drinking. I can buy more fish but it is hard to replace a liver!!

EDIT?
Talked to the old hat that I used to work with and he has much more experience with the salt and suggested a very crude method which he uses. IOt does have some "yuck" factor built in but he suggested a quickie way to find if it is calcium or salt. scrape a bit off and taste it! A small chunk of calcium is going to give a gritty bit of limestone which doesn't dissolve easily, where salt deposits will be much different and dissolve much quicker. He also suggests spitting after the test!!!!

Last edited by PlantedRich; 08-15-2018 at 02:44 PM. Reason: added info
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post #4 of 12 (permalink) Old 08-15-2018, 07:52 PM
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Quote:
When tested with the API GH test kit it is less then 1 degree hardness.
The GH test mainly detects calcium and magnesium. It may also detect a few other element which are normally not abundant. So your GH test is indicating that you have very little calcium and magnesium in the water.

Quote:
It is well water and the pH is 4.5 consistently. TDS is around 100.
Unlike the GH test TDS measures ALL disolved solids in the water. It is in agreement with your GH test. You have soft water.

A cold rain drop can have 2 times the atmospheric concentration of CO2 in it. About 800ppm. If the rain soaks into the ground fast enough that CO2 will end up in the aquafer. A PH of 4.5 indicates your aquafer is fully saturated with CO2. There could be other acids dissolved in the water but CO2 is the most common.

Quote:
Recently I suspect is was responsible for ruining an RO membrane which dropped down to 50% efficiency within a few months of light use.
Two things will kill a RO filter really fast. High chlorine levels and high iron levels. If your well system has a chlorine system to sterilize the water make sure that it is working properly. Iron manganese and other similar metals don't dissolve easily in water. However they will dissolve easily in very acidic water. I suspect most of the deposits you see are from metals like iron and high metal content will plug up a RO filter very fast. Once the well water has degassed the PH will change (probably will go up) and the iron will precipitate out of the water.

The first thing I would do is to get your water tested by a lab. It is possible that your water has unhealthy levels of lead uranium or other harmful metals. With that information a well maintenance company can suggest equipment and methods to reduce the metal content.

Once common solution is to treat the well water with a water softener. This will use salt and a rechargable resin that will remove most of these metals from your water. Your RO system would then last a long time on one RO filter. The filter would also remove the sodium bicarbonate the water softener adds to the treated well water. Water softeners increase KH.
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post #5 of 12 (permalink) Old 08-15-2018, 08:39 PM
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Low pH + low gH + low TDS but heavy mineral deposits. That leaves non-conductive minerals, with silica being the most common.
I would certainty have the water lab tested.
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post #6 of 12 (permalink) Old 08-15-2018, 11:46 PM
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If you're feeling brave, taste the white stuff. If it tastes salty, well ...salt.
If it tastes bitter/sour, maybe calcium.

you're drinking it anyway.

Better: have your S/O taste it!
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post #7 of 12 (permalink) Old 08-16-2018, 12:40 AM Thread Starter
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-The taste was chalky and tastless.

- Flame test of the white chemical resulted in a faint green flame (this indicates copper iirc). Although my lack of platinum wire may have skewed the results.

- I forgot to mention that this water leeches metal from brass fittings, causing then to crack. It also destroys copper hot pipes, causing pinhole leaks.

- Also whenever I use API tap water conditioner it always results in these little brown flakes precipitating out. Nobody at the fish store has ever seen that before.

- We have no chlorine being added to the water. I always assumed that there is no chlorine in well water. I will check this now.

- The filter is a high end RO system with a 1 micron sediment and dual carbon (also 1 micron)

Thanks everyone for the great responses!

Last edited by cds333; 08-16-2018 at 01:10 AM. Reason: changes
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post #8 of 12 (permalink) Old 08-16-2018, 01:30 AM
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Chalky - calcium carbonate? Carbonates burn green ...I think. Water passing through limestone.
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post #9 of 12 (permalink) Old 08-16-2018, 02:57 AM
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Private, community, city, or what level of well is this? Chlorine treatment might be found on any and might not be obvious at first look. I think of limestone/calcium as being hard and alkaline water which doesn't seem to fit what your tests are showing. I might ask about the first picture. Is that a look inside a supply line, not a drain line? Looks like it might be a form of braided flexible line??? I don't find limestone sticking to that type line but it does do a real job of clogging old iron pipe to reduce flow. I'm not up on it making leaks as much as simply sticking to the walls and gradually reducing the flow but that is a decades long process in many cases. Old houses where the pipes may be a hundred years old? I don't find them leaking, just not letting water pass.
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post #10 of 12 (permalink) Old 08-16-2018, 04:56 AM
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I think you should do the following.

Put some tap water in a bucket and measure the PH each day. CO2 outgassed rapidly from water so if you have a lot of CO2 in it the PH should rapidly change. Also monitor the water for a color change. As the PH changes element my precipitate out.

You probably have a KH test (GH and KH tests are frequently sold together). What is the KH of your tap water if it is high it would support the CO2 explanation for your PH.

Also to measure a PH of 4.5 you were probably not using a typical aquarium test kit. Most will not read a ph that low. If you used a electrical PH sensor was it calibrated and how did you calibrate it?

Quote:
Chalky - calcium carbonate? Carbonates burn green ...I think.
Calcium apparently produces an orange flame. Green can be caused by copper, barium, and boron. It appears that only copper fits the GH, PH information we have.

https://www.thoughtco.com/flame-test...allery-4053133

Last edited by Surf; 08-17-2018 at 07:47 PM. Reason: Please use the edit function for back to back posts to keep threads cleaner
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post #11 of 12 (permalink) Old 08-18-2018, 07:27 AM Thread Starter
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The picture is a supply hose which carries both hot and cold water; I used multiple pH meters which were two-point calibrated. KH does not even measure, it is yellow after one drop (blue to yellow transistion indicates degrees of KH)

The well is located in a suburb of Baltimore.
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post #12 of 12 (permalink) Old 10-06-2018, 08:28 PM
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Here's the mineral analysis for the city of Baltimore. If you are nearby I would assume it's close to the same. https://publicworks.baltimorecity.go...RTON%20LAB.pdf
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