dH and Gh? Are they the same?

[JackBlasto]

Trying to get a better grasp on KH to GH I'm reading and see this:


0 - 4 dH, 0 - 70 ppm : very soft
4 - 8 dH, 70 - 140 ppm : soft
8 - 12 dH, 140 - 210 ppm : medium hard
12 - 18 dH, 210 - 320 ppm : fairly hard
18 - 30 dH, 320 - 530 ppm : hard
higher : liquid rock (Lake Malawi and Los Angeles, CA)

IS the dH (degrees hardness) the same as GH?

I am trying to interpret my readings on a conductivity meter that doesn't output ppm... it outputs micro seimens so I'm using this conversion: 1GH = 17.9 ppm = 33 micro siemens

Well, how does dH play into all this?

Thanks

 

[JackBlasto]

AND if dH IS the same as gH then can I go ahead and make this statement to include microseimens and not be butchering science?


0 - 4 dH, 0 - 70 ppm : 0-132 microseimens very soft
4 - 8 dH, 70 - 140 ppm : 132- 264 soft
8 - 12 dH, 140 - 210 ppm : 264 - 396 medium hard
12 - 18 dH, 210 - 320 ppm : 396 - 594 fairly hard

 

[aqua_chem]

It depends on how it's being used, but I would take dH to b synonymous with dGH.



Microsiemens isn't really a good substitute for ppm. It doesn't convert well between units, unfortunately. Here's some reading on the topic.

http://appslabs.com.au/salinity.htm

 

[JackBlasto]

Thanks for the reading. I read through it and tried my best to understand the stuff I didn't. What I concluded was that depending on the salt in your water it can mess up the readings. So now I ponder, in RO water would it give accurate readings because there is no salt?

 

[aqua_chem]

RO water would probably have a capacitance near 0 uS/cm, so it's not a problem. "Salt" in this case refers to any ionic compound, and salt content refers to the relative amounts of Ca++, K+, Na+, Mg++, NO3-, Cl-, CO3--, etc, in the solution. Because it's hard to control, you can't really translate capacitance into direct measurements of concentration very well in most circumstances.

 

[JackBlasto]

Aquachem, I know you'll be able to answer this better than anyone. Why did I buy a conductivity meter that reads microseimens? Haha... Seriously though... I think it was a hundred bucks... A tds meter is $15 what benefit is my conductivity meter or have I simply made a huge financial mistake ? Any input since you actually know the difference between these meters...

 

[aqua_chem]

Well, specifically, what do you want to measure with it?

 

[JackBlasto]

Well, I thought when I got into this that that was the instrument needed to test the softness of freshwater best.

When I bought it I read on Hanna Instruments website regarding their conductivity meter "This precision instrument is perfect for serious discus keepers who add trace elements to pure water to achieve a reading of about 70 µS. Also useful for determining membrane effectiveness of reverse osmosis units. Regular tap water measures about 300-500 µS; good quality RO water measures 5-15 µS."

Well, that was my goal. I wanted some good RO water for Discus.

Thing is now that I have read the documentation you've provided me it almost seems that a cheap TDS meter does the same thing, if not more accurately.

I mean what is the advantage of taking a reading in microsiemens since it doesn't necessarily convert to ppm because of a variety of factors? It seems to me that everyone spouting off numbers always is doing so in ppm.

Does microsiemens read the content of the water, if interpreted correctly, in a more detailed way?

 

[JackBlasto]

So I DID get a $15 tds meter off amazon and I'm pretty sure I didn't need the conductivity meter as the tds meter does exactly what I need. I'm still confused as to why anyone needs the conductivity meter rather than the tds meter...