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Re: CO2 for a 200 gallon

David wrote:
"I change water in these tanks so frequently that the tank's pH
drops much. It tends to stay around 7.1 to 7.2. The potted
anubias, & Java's grow "OK".
Is there a specific buffer anyone would like to recommend me to
use in
these tanks? I have tryed:
"Discus Buffer", no good, too much algea from the phosphate.
Muriatic Acid, no good, wipes out the KH
"Acid Buffer", supposedly good for planted tanks, but a lot of
folks on various forums are leary of it.
Kent Marine's "pH Control Minus" , my current choice as it
claims to be
phoshate free, & is the most economical of the brands I have

Cheapest easiest long term solution would be to use CO2 gas.

"In my other tank, heavily planted & using tap water, I can't
seem to
inject enough CO2 to get the pH to come down much lower than
6.9, which
is first thing in the am before the lights come on. This tank
has GH
around 300 to 350 ppm, & a KH of 4 degrees.
Going by the CO2 chart, this puts me in a decent CO2 range
before the
lights come on.
If I check the pH in the afternoon, it tends to have risen to
about 7.1
to 7.2, dropping me back out of the "ideal" CO2 levels.
The tank is 200 gallons, with dual overflows & a very large
sump. Water
is circulated with an eheim 1060, probably around 500 gph.
CO2 comes from a 20 gallon tank with a premium Victor regulater,
needle valve, bubble counter, & a homemade reacter in the sump."

Add some sponges to the overflow to reduce splashing. Feed the
CO2 output from the reactor directly into the return pump
Have a spray bar return and point this downward. Get a better
needle valve, ARO's are junk. Get a larger pump for the reactor.

" The
bubble rate is running faster than I can count. The reacter is a
long python, full of bioballs, with a rio 800 forcing water

In the tank or in the sump?
If in the sump follw the above, if in the tank add some current
to mix the outflow from the CO2 good.

"There's enough CO2 bubbles going in that all the bioballs are
a lot of the gas, & a small amount of CO2 collects at the top of
tube. A few bubbles get pushed all the way to the bottom, &
escape out
the 1/4" holes drilled near the bottom of the tube. There is
also an
airline valve mounted in the top cap of the tube, with an
attached which runs over to the circulation pump's intake.
Opening this
valve sends a few bubbles to the pump, which come out into the
tank as
fine bubbles.
I can't see how this arrangement would be unable to dissolve
enough CO2
to get me in the optimum range. Maybe I need to crank the bubble
rate up
even more?"

No, a well set up system should run about 3-4b per second for a
200 gallon. 

"I am almost" to the point of investing in a controller, because
I am
concerned that a much higher bubble rate would cause problems
oversaturation of CO2 at night."

Well buying one won't solve this issue. You just need to get the
CO2 well mixed. You can mix it in the sump and have it come back
via the return or mix it in tank with some extra flow near the
outflow from the reactor.
Tom Barr

Any & all input appreciated.
David Modine

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