Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh =
7.5 ppm CO2, in the morning after lights on for a couple hours it checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.
Should I be looking at decreasing my surface agitation of the power filter?
Thanks.

--
Paul

"You can make it foolproof, but you can't make it Damned foolproof."

On Sun, 29 Sep 2002 10:25:36 -0700, "Paul"
wrote:

Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh =
7.5 ppm CO2, in the morning after lights on for a couple hours it checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.

Something wierd there, KH does not change back and forth. If your
test kit is showing that it does, then something is wrong, quite
possibly with the test kit.

But, in any case, it definitely looks like the CO2 level is dropping
during the day. And that isn't a good thing, since the plants growth
will be slowed, increasing the chances for algae to grow.


Chuck Gadd
http://www.csd.net/~cgadd/aqua

Paul wrote:

Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh =
7.5 ppm CO2, in the morning after lights on for a couple hours it checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.
Should I be looking at decreasing my surface agitation of the power filter?
Thanks.

Paul,

It is unlikely that KH would swing 1 point in a few hours. I am guessing that
you are measuring pH and KH, then calculating CO2 from them. If so,
inaccuracies in the KH measurement are causing wide apparent CO2 swings.

Is your test kit fairly new? Mine allows doubling the accuracy by doubling the
amount of water. Does yours?

"Paul" wrote in message ...
Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh =
7.5 ppm CO2, in the morning after lights on for a couple hours it checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.
Should I be looking at decreasing my surface agitation of the power filter?
Thanks.

How are you adding the CO2?
I think if you supply enough current in the water column, have the out
flow from the CO2 reactor/diffuser shoot downward inot the plants,
that should help things.
You may need more flow in/out of the CO2 reactor.

The plants are using it up faster than the CO2 system you presently
have set can supply it , hence the loss near the end of the day and
when the plants are not using it at night, the levels slowly builds
back up to 27ppm etc.
Regards,
Tom Barr

Is your test kit fairly new? Mine allows doubling the accuracy by doubling
the
amount of water. Does yours?


You can do this with all "KH" test kits. It's really just a titration for
alkalinity down to pH 4.2 or somewhere near there (forget the exact
indicator they use).. so double the volume and you double the ammount of
acid needed to hit this endpoint.

Jeff Ludwig

"Dave Millman" wrote in message
...
Paul wrote:

Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh
=
7.5 ppm CO2, in the morning after lights on for a couple hours it
checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.
Should I be looking at decreasing my surface agitation of the power
filter?
Thanks.

Paul,

It is unlikely that KH would swing 1 point in a few hours. I am guessing
that
you are measuring pH and KH, then calculating CO2 from them. If so,
inaccuracies in the KH measurement are causing wide apparent CO2 swings.

Is your test kit fairly new? Mine allows doubling the accuracy by doubling
the
amount of water. Does yours?

I have the Aquarium Phar. test kit, about 10 months old. When I checked the
KH at 9 drops(9dkh) the water just started changing color to yellow, it
took one more drop to completly change it to bright yellow. I double checked
it with a newer Tetra Test kit which agreed with the 10dkh of American Phar.
The second test was definitely 9dkh. So maybey there was 1/2 point diff. The
Tetra Test does allow more accurate testing, will have to give that a try.

" wrote in message
om...
"Paul" wrote in message
...
Checking the CO2 in mid afternoon I find that pH is 7.6 and KH is 10dkh
=
7.5 ppm CO2, in the morning after lights on for a couple hours it
checks, pH
7.0, KH 9dkh, CO2 = 27 ppm. Is this depletion good, bad or indifferent.
Should I be looking at decreasing my surface agitation of the power
filter?
Thanks.

How are you adding the CO2?
I think if you supply enough current in the water column, have the out
flow from the CO2 reactor/diffuser shoot downward inot the plants,
that should help things.
You may need more flow in/out of the CO2 reactor.

The plants are using it up faster than the CO2 system you presently
have set can supply it , hence the loss near the end of the day and
when the plants are not using it at night, the levels slowly builds
back up to 27ppm etc.
Regards,
Tom Barr

I use a pressurized system. What would be a good reading for the morning?
Maybe I should up the bubble rate?