Re: Acid buffer

>  You can raise KH with baking soda or calcium bicarbonate.  The latter will 
> also raise GH, I think.

Won't baking soda raise the pH too?  I put some sodium bicarbonate into some
water (about 1 teaspoonsful into 1 cup water) and the pH shot up.  Maybe it
won't be so bad if I just add a few teaspoonfuls to the tank (125 gal) & see
what happens.

I also decide to tip the rest of my peat (about 1/4 of a 350 cubic inches bag)
into a bucket of hot tap water (350 ppm CaCO3, pH 8.2).  After a day the pH
in the bucket was down to 6.6 and the GH < 1, KH = 8.  I siphoned off the
tea colored liquid & added it to the tank & added more hot water to the bucket.
I'm hoping this will be a good way to increase KH also, but I'm wondering what
happened to the GH?  will the CaCO3 leach out of the peat at any time?

Now, to change the subject:
> Also, does anyone here run a denitrator? (I think George does.)  Any comments 
> on how well it works and what effect it has on the plants?

Yes, I run a denitrator.  It's a commercial one, Aquarium Products or some name
like that.  It's basically a coil of black tubing & some bioballs inside a
large clear hard plastic cylinder.  It runs almost constantly on the tank
except that my inlet for it is from a power head & the tube often comes out.
It definetely reduces nitrates.  With it & a fish load of approx. 0.5 inches of
fish per gallon in a 125 gal heavily planted tank & 5 gal water changes per
week I maintain nitrates approx. 0 (sometimes gets up to 5 ppm if I get lazy
about gravel vacuuming).  Effect on plants: very positive when they're not
being strangled by hair algae which was a major problem for me before I
decreased fish load & added denitrator & CO2.