Regarding PPM and TDS meters

I know there are lots of questions out there about this and I scanned to try and find an answer first before posting this, so if you know of a topic that covers this please let me know!

I just got a TDS meter and calibrated it to a 1000ppm solution. I then checked my tap water and the reading was extremely low - like impossibly low for tap water from what I expected. That value was a whopping 15! As far as I know this house doesnt have RO or any other type of prefiltration. I also cant find any info about a multiplier being used in the results where 15 might = 150. The refrigerator water has a carbon filter and that reading came out to 11. Is this possible? Or is the meter junk?

i saw in the Q&A someone asked a relatively similar question and got a pretty obtuse answer that I am too dense to understand this morning.

If you calibrated the meter in 1000ppm solution and you’re reading 1000ppm then your 15ppm reading should be correct. Which would suggest you have an RO system. Check another source like your bathroom as those lines don’t usually get connected to RO systems

You’re not down steam of a water softener after you? If so, check your outside faucet as those usually are not softened water.

im double checkign with the owner, but I have not seen any such system anywhere in the house, particularly the basement. looks like its coming right off the street as usual.

I recalibrated and still am reading 15ppm.

Water out of the house in the backyard is the same.

@GoneFission, not that i am aware of. I found this about our areas water supply:

City’s water is very soft. The hardness of watershed water is typically 3-8 ppm – approximately ¼ to ½ a grain of hardness per gallon. City’s groundwater hardness is approximately 80 ppm (about 5 grains per gallon), which is considered moderately hard.

also, with regards to filtration:
Neither the groundwater nor source water is filtered. The source meets the filtration avoidance criteria of the [Surface Water Treatment Rule]

Is it unreasonable to conclude that municipal watersupply could be this clean?

Looks like it. That’s pretty wild

yeah im having a hard time not assuming this meter is junk!

Take some soil and mix it up in a swirl and see what the meter does.

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If its reading the 1000 correctly and your watershed is showing 3-8, looks like it may be working properly

that aint right. Does it have a reset function? Reset, don’t calibrate, and test again.

Also, be careful how far down in the water you put it…they get damaged if you put them in to far. There should be a line.

i dont see any reset function in the instructions. possibly battery removal/replacement. i did manage to get the reading over 100 with more soil in that water. but i guess i would have expected it higher. i wonder if i should let the soil soak for a while and dissolve more then check again.

You can wait, but it is off; if you put it to far down in water, it could have gotten damaged, or it could just be faulty. Amazon is awesome; throw them an email and the will get a new one right out.

yeah ive already sent for a replacement :wink:

its just too good to be true.

but if the next one reads the same, i probably still wont believe it.

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I don’t calibrate my TDS meters, but have never had any trouble with them. :open_mouth:

this one comes calibrated to 342 so i got the 1000 solution since ill be need it for higher PPM counts. i did not, however, take an immediate reading out of the box - opting instead to calibrate first.

this time ill try it out of the box and see if its any different before and after calibration

They will automatically read higher ppm; most put an X after the number meaning to multiply by 10(so 100x is 1000). So it may be the low numbers you saw just needed to be multiplied by 10 since you had calibrated it to 1000 already. Make sense?

Yeah first thing I did was try to find out if there was a multiplier but it doesnt appear to be the case. the instructions say to calibrate to 1000 if you are routinely reading for higher ppms. either i have pristine water or this thing was off out of the box. guess ill know monday! thanks for your input

It looks like you have good data on your water supply. Amazing actually. If you’re reading 1000 in a 1000 solution that’s also good. Dirt isn’t going to necessarily increase your reading. Drop a pinch of table salt in there.

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If there are nutrients added to the soil, I should see a hike once dissolved… At least that’s my understanding. I’ve got a new meter on the way anyway I’ll run the tests again before and after calibration ( salt included). Will post results here. Thanks all!