CO2 input into powerhead

Hi everyone,

This morning I decided to add an extra yeast + sugar CO2 bottle to my 125 gal
tank (I had three 1 litre bottles going but only had 7 ppm CO2).  I decided
to use a bigger bottle (2 litre) as suggested by someone on this list, and
to put the airline tubing from the bottle into the air input hole on my
penguin 550 powerhead (I don't normally have air going in to this).
Anyway ... after about 10 or 15 minutes I noticed small amounts of fine
bubbles coming out my powerhead & after about 30 mins the yeast + sugar
mixture was foaming quite a lot - this normally takes about 2 hours to
happen.  It is not a particularly warm day in Madison WI today (actually
quite cool & raining) so I can only assume that the "sucking" action of
the powerhead is causing the reaction to go faster.  Is this good?  It's
been running for over an hour yet & neither pH or CO2 concentration in 
the tank have changed.

Unrelated issue (kind of):  Using peat as substrate
I have been using peat in a bucket to make "peat water" to add to my tank
(instead of adding peat cause it goes everwhere & clogs up my filters).
The peat seems to be exhausted of its acidity but is still lowering the
hardness of hot tap water added to the bucket & siphoned off every day
or two.  Anyway ... in about a month I will be moving apartment & I'm
thinking of dismantling my 25 gal tank & using laterite in the substrate
(previously it was just gravel).  Would adding this "used" peat be

Also, kinda unrelated: pH test kits
Someone asked about test kits & I have been using Red Sea fish pharm kits
for Fe and pH and I was wondering if anyone else uses them or uses something
else.  For nitrate, nitrite and CO2 I use LaMotte kits (I keep nitrates
below 10 ppm and I'm trying to get CO2 to at least 15 ppm & don't have to
worry about getting to near dangerous levels of 30 or 40 ppm; with nitrates
I have algae problems if they get above 20 ppm; nitrites I keep at zero;
Fe at 0.1 ppm; pH 6.8).  I use tetra tests for KH and GH (does anyone else
make kits for KH and GH?  I haven't seen any.  I have KH 3 and GH 6 right now).