pH Changes

Neither salt*, sodium chloride, nor Flourite affect the pH/KH.

Bioacidification = Nitrification is an acid-generating process, meaning that it uses up alkalinity/KH. With the passage of time, the oxidation of ammonia to nitrate lowers the KH in the tank.

* Provided that it really is sodium chloride. "Aquarium salt" is a product with no definition, nobody knows or few admit what the ingrdeients list would be.
 
Ah! I measured the pH in my betta tank, it's a planted Eclipse System 6 (6 gallon), 5"-6" of flourite, a catlinite cave (a "mud" stone, not steatite), and a piece of bogwood. This is an older tank and I do weekly water changes on it. The pH, I haven't done the water change yet, is 7.4. That's in keeping with the other tank.

So, the water comes out of the tap at 7.8. When it sits overnight it's 8.0 and when it's in these two aquariums it drops to 7.4.

Mindate.org says calinite (not a valid mineral species) is composed of pyrophyllite and sericite. These pieces are Utah pipestone, which is one of the harder ones.

Pyrophylite: Al2 Si4 O10 (OH)2
Blah, maybe someone else can make sense out of this chemical mumbo-jumbo: http://www.mindat.org/min-3323.html

What I see are common between the catlinite -- it's Utah catlinite, so its hardness is much higher than 1½-2. I'd say more like a 5, in keeping with the steatite in the other tank. The steatite IS harder, I'd say about 6. There are many different varieties of pipestone. The softest is Minnesota pipestone, which is about a 2-3.

Anyhoodle, I see talc and silicate in both. Methinks talc may bear looking into?

Roan
 
You know what I'm going to do? I'm going to get a cup of water, put a piece of pipe or soap or steatite in it and let it sit overnight -- or for a couple of days -- then measure the pH.

Dang, I'm curious.

Roan
 
Me three and I'm going to test it late this afternoon. To be honest, the only thing I can think of that *could* drop it -- meaning it's the only thing I have that I don't see others using -- are those particular rocks.

Roan
 
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