re:Buffering KH & lowering pH, with no CO2 (yet)

>I have not yet had the time to build and install a CO2 generator, but it 
>is not from a lack of desire.  In the meantime, I need to decide how best 
>to lower the pH while maintaining the KH at around 3 or so.  
>I think David and others have said they 
>have used vinegar to achieve the drop.  That's the only method I've heard 
>thus far, other than installing a CO2 generator.  Are there any other 
>ways to do this?  [snip]
>Thanks for your ideas.  Mark.

As far as I can tell, adding an acid will tend to lower your KH.  I haven't 
studied my pH chemistry since college, and some of what I'm thinking seems to 
contradict.  But I'm thinking that adding vinegar will drop your KH.  The 
contradiction is: I don't think that adding CO2 will drop your KH.  On the 
other hand, I might be completely wrong, and you might be adding an acid buffer 
that will tend to more firmly stabilize your pH (until your plants decalcify 
the water).  I used to add vinegar way back when, but I didn't and still don't 
know if small quantities of it are bad for fish.

You can set up a couple of CO2 generators in about 15 minutes total time (minus 
getting the ingredients).  Bore (or drill) a hole in the plastic cap of each 2 
liter bottle that you will use and poke about 2" of rigid airline halfway in. 
Make the lower cut at a 45 degree angle to help keep swill in the bottle and 
not in your air lines/tank.  Seal each cap liberally with clear silicone and 
let it sit for a day.  

Then fill the bottles up with 2 cups sugar, 1 tsp yeast, 1 tsp baking soda (for 
pH buffering) and up to 3" from the top with water.  Hook the bottles up to air 
lines and run them to the intake of a pump or powerhead.

OK, I'm estimating a little low on time, but you can do it while enjoying the 
tank (hopefully you get a few minutes a day to enjoy).

My system produces enough CO2 for an average of a bubble or two every second or 
two, despite back pressure from my reactor pump and what smells like a tiny 
leak when I get really close to the bottles.

I've mentioned vinegar and have seen a few other fleeting comments about it, 
but for the most part, it seems to be a dark art.  Does anyone have any real 
information about vinegar in an aquarium?

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc.
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