threatco
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Perhaps I'm slow &/or stupid but if ph just tells you the alkalinity or acidity of the water how is alkalinity not high pH, what is it then?
Its was my understanding that TDS (Total Dissolved Solids) are what are measured with these meters, are there not other inert solids that don't effect the alkalinity or acidity of water? If so how can you tell anything related to this from the ppm read?
I'll take a stab at it.
It's all about balance.
Here is a picture of "hard" water.
The red t-shirt boy is all alkalinity. A whole bunch of carbonate and bicarbonate molecules as a ratio (parts per million).
Blue T-shirt boy is your acidity. A few weak acids in your water, but just not enough to lift up red tshirt boy.
In the above pic, you need to add a bunch more blue shirt kids to move the PH down.
Below is a pic of "soft" water, or water with very little acidity or alkalinity present as ppm.
It may be sitting in the "high PH" range. But that is based on very little actual alkalinity.
You put a single blue shirt kid on that top end, and whamo blamo, you quickly have "low PH"
This is what he means by PH being a crude way to measure this.
I test my 45 ppm tap water, it says 7.3.
But that does not tell me what so ever how much acid I need to add to get it to 5.5. In my case it is very very very little. (like a few drops per 20 gal)
Someone else might test their 400 ppm 8.0 tap water, and maybe they need 20-30x more of the same acid then I do to get to 5.5
And that is not because there 8.0 is that much higher then 7.3
It's because the 400ppm tap water could be 80% carbonates and bicarbonates, that neutralize the acid I am adding.
:)
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