Not Co2 again!

["Sharon Stewart" <sharon at stewartcentral_com>]

Hello, all!

Well, I find myself in need of setting up my Co2 system on my 38 gallon
tank. I'm having wicked pH problems, <sigh>. The parameters are:

38 gallons
55 watts compact fluorescent
tap KH 2, sometimes 3
tap GH 6 now, usually 8 or more in the Spring-Summer
tap pH 7
tank KH-2 for a day or so after water change, not measurable after that
tank GH-6
tank pH, see below

I change the water weekly. By the end of the week I have no KH that I
can measure, and the pH swings up during the day, and down at night.
Usually what I would see happen is the pH swings from 7 to 7.6 after a
water change, then over the course of the week the nighttime pH low
would work its way down to 6.3 or so.

This week, my always entertaining pH is swinging to over 8 during the
day--I panicked and turned off the lights once it hit 8.1. Once the
lights were off, the pH dropped right back down. The only thing I've
changed is I added 3/4 of a tablet of potassium gluconate.

So, I went rummaging in the basement for the pieces to my old CO2
system. I'm missing my dual gauge regulator, darn it! I have the needle
valve and solenoid from my Sandpoint Genesis 2 system. And I swiped a
single-gauge regulator from my husband's kegerator--"taprite series 740"
is the name on it and it is marked to 60psi--but it doesn't have the
right hose barb on it. 

I'm limping along now with just the needle valve/solenoid, a dupla check
valve and, horrors, an air stone (while washing the Sandpoint reactor
this morning I snapped a main piece of it--I'm not having a great day!).
I don't think my plants are getting any of the Co2, but my pH isn't
skyrocketing. The solenoid turns on and off every 10 minutes or so. Not
the best, I know, but I will have to order a new reactor.

So, is there any way I can get the Taprite regulator to work with the
Sandpoint needle valve/solenoid combo, or should I buy a new setup? I'm
guessing it might be time to retire the Sandpoint needle valve combo.
And should I be adding some baking soda to up my KH? And, if I should
add baking soda, how long will the effect last? In other words, how
often do you have to add it?

I've read everything I could get my hands on and my head is swimming, so
any advice is appreciated. I'm guessing that I'm seeing biogenic
decalcification, but that is only a guess. 

Thanks a million!

Sharon Stewart