kh weirdness

Thanks for all of your suggestions.

The tank had been set up previously so I am fairly confident about the
behavior my non-co2 water values. (The little minnows I kept sadly
were infected w/ tb and died off. I took the tank apart and gave
everything a good bleach soaking/scrubbing followed by lots of rinsing
and decholorinating, a new filter pad and bio-wheel, and new gravel.)
The ph is 7.0 out of the tap, 7.5ish after standing (CO2 dissolves),
and used to fluctuate from 7.8 to 8.2 with the presence of a plant.
The kh had always been stable at 4.5.

So, you're right, something is either screwy with the gravel or the diy
CO2. I removed the CO2 for now and changed the water in the tank, and
am going to observe the kh/ph with just the gravel. I think I'll also
try the CO2 container test you mentioned. Hopefully I'll get some
clues!

I'm occasionally in NYC and enjoy the famously soft water. ((My
friends tell me it's the secret to those delicious bagels.)

I think I solved the mystery.

The gravel + water on its own yielded no rise in kh, and neither did
the CO2 into a bottle. But, when I was running the CO2 into the tank I
used a check valve. (I didn't use the valve when I ran the CO2 into
the bottle.)

Well, the check valve had some type of filtering material. It was the
only valve in the fish store and I didn't think much about it when I
bought it. I found another valve w/ no filter material and tried
injecting the CO2 into the tank again, and, no extra kh.

I feel silly because I hadn't noticed this before posting!

Robin wrote:
I think I solved the mystery.

The gravel + water on its own yielded no rise in kh, and neither did
the CO2 into a bottle. But, when I was running the CO2 into the tank
I
used a check valve. (I didn't use the valve when I ran the CO2 into
the bottle.)

Well, the check valve had some type of filtering material. It was
the
only valve in the fish store and I didn't think much about it when I
bought it. I found another valve w/ no filter material and tried
injecting the CO2 into the tank again, and, no extra kh.

I feel silly because I hadn't noticed this before posting!

Hey, I'm glad you found the culprit. Now, on to the real business of
fish and plants!

Contact me off-line if you want a copy of my ph/kh/co2 chart. It
prints nicely and is good to keep taped up near your tank.

montagnard_army at free-email-provider-beginning-with-y dot see-oh-em.

--
Trapper

Buy a box of carbon dioxide control system, but when it was all over and do, and I want to see my tank, and not, as certain types of scientific projects. This is a problem to find a balance between the tanks, and more balanced technology achieve that balance, so you can sit back and enjoy it.