TDS Meter Results

[iclown]

I couldn't find a section for water chemistry so I just threw this in here. Anyhow, I just got my HM DIGITAL "COM-100" TDS Meter with ATC. It says "The COM-100 is factory calibrated to a 1413uS KCL solution." So I simply popped the cap off and placed it into each samples with rinsing between samples. Additionally, I set the MODE to TDS-ppm (with 442 conversion factor and temperature coefficient).
So I tested 4 water samples:
1) My Drinking Water from the Vending Machine: 12.2 ppm @ 19.2 Degree Celcius
2) Tap Water: 114 ppm @ 24.2 degrees celcius
3) Sunnyside Farms Distilled water: 0.8 ppm @ 20.4 degrees celcius.
4) LFS water: 276 ppm!!! @ 21.8 degrees celcius
Is my LFS screwing me over? Can the LFS water be affecting the health of my fish and my "future" soft corals?

 

[flower]

Quote:
Originally Posted by iClown http:///forum/thread/385284/tds-meter-results#post_3378157
I couldn't find a section for water chemistry so I just threw this in here. Anyhow, I just got my HM DIGITAL "COM-100" TDS Meter with ATC. It says "The COM-100 is factory calibrated to a 1413uS KCL solution." So I simply popped the cap off and placed it into each samples with rinsing between samples. Additionally, I set the MODE to TDS-ppm (with 442 conversion factor and temperature coefficient).
So I tested 4 water samples:
1) My Drinking Water from the Vending Machine: 12.2 ppm @ 19.2 Degree Celcius
2) Tap Water: 114 ppm @ 24.2 degrees celcius
3) Sunnyside Farms Distilled water: 0.8 ppm @ 20.4 degrees celcius.
4) LFS water: 276 ppm!!! @ 21.8 degrees celcius
Is my LFS screwing me over? Can the LFS water be affecting the health of my fish and my "future" soft corals?

At the LFS.....Did you test the water they sell, or the water the critters are swimming in?

 

[aquaknight]

Need details on what "LFS water" means. Assuming you test the water at home? How did you transport the water home (in what)? How does the LFS store their water? Any chance the LFS water was put into a container that was used to either mix salt, or held saltwater for some period of time?
Basically unless you're testing the LFS's water right out of their RO/DI unit, the TDS readings will always be higher. That said, 276ppm is high. But you're tap water is pretty darn low (I have ~250 here, most have between 200-400). I would see if the LFS would see if you could compare your TDS Meter to theirs.
These hobby tools, even a sightlier more spendy one like your COM-100, is far from anything "Lab Grade." I personally use the shotgun approach and have 3 meters, a decent Hanna pen-style meter, a cheapy pen-meter, and then the in-line meter on my RO/DI.

 

[monsinour]

Quote:
Originally Posted by AquaKnight http:///forum/thread/385284/tds-meter-results#post_3378407
Need details on what "LFS water" means. Assuming you test the water at home? How did you transport the water home (in what)? How does the LFS store their water? Any chance the LFS water was put into a container that was used to either mix salt, or held saltwater for some period of time?
Basically unless you're testing the LFS's water right out of their RO/DI unit, the TDS readings will always be higher. That said, 276ppm is high. But you're tap water is pretty darn low (I have ~250 here, most have between 200-400). I would see if the LFS would see if you could compare your TDS Meter to theirs.
These hobby tools, even a sightlier more spendy one like your COM-100, is far from anything "Lab Grade." I personally use the shotgun approach and have 3 meters, a decent Hanna pen-style meter, a cheapy pen-meter, and then the in-line meter on my RO/DI.
Good to see someone doing more than one TDS meter.
Of the 3, what one do you think is the most accurate?

 

[aquaknight]

The Hanna (98311). Inline's don't compensate for temp and can be off.

 

[iclown]

Quote:
Originally Posted by AquaKnight http:///forum/thread/385284/tds-meter-results#post_3378407
Need details on what "LFS water" means. Assuming you test the water at home? How did you transport the water home (in what)? How does the LFS store their water? Any chance the LFS water was put into a container that was used to either mix salt, or held saltwater for some period of time?
Basically unless you're testing the LFS's water right out of their RO/DI unit, the TDS readings will always be higher. That said, 276ppm is high. But you're tap water is pretty darn low (I have ~250 here, most have between 200-400). I would see if the LFS would see if you could compare your TDS Meter to theirs.
These hobby tools, even a sightlier more spendy one like your COM-100, is far from anything "Lab Grade." I personally use the shotgun approach and have 3 meters, a decent Hanna pen-style meter, a cheapy pen-meter, and then the in-line meter on my RO/DI.
I have a 5 gallon container that I hand to the LFS. They go into the back after I tell them I won't RO water. They come back and hand me my containers and I pay. I did test the water at home by the way. That was how I received the water. I guess I should go back in and check clearly with them.