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Re: [AGA-Member] pH shock / climbing pH

Kirsten Klinghammer wrote:

I'd forgotten an important thing which was explained to me about the CO2
bottle - to turn it on full. I had it on really low before (just barely
on), then was trying to set the regulator and the needle valve to the flow I
wanted. The flow kept petering out on me, so this morning I turned gas on
at the CO2 bottle to a higher level - while foolishly at the same time
increasing my bubble rate. What got me into the worst trouble, though, was
spending three hours with a repairman in the kitchen and not remembering to
carefully monitor the changes I'd made.

I've now reached the friend from whom I got the CO2 bottle, regulator, and
needle valve (he's out of town and just got my email), and he walked me
through everything - and this time I WROTE IT DOWN, as I should have done
the first time around. I now also see the need for using a bubble counter.
I thought I could count the bubbles accurately enough in the reactor, but I
was wrong. My friend also reminded me to double-check my KH, which I'd
forgotten to do this morning. With the pH that went down to 6.5 and my KH
of 16 (making 144 ppm of CO2), I'm surprised my poor fish managed to survive
at all... no wonder they were all trying not to breathe! I'll be shooting
for a pH of 7.5 once I get everything properly fine-tuned.

Aside from my CO2 overload problem this morning, I'm puzzled why my pH keeps

It shouldn't be drifting that high that fast when your wellwater isn't that hard. Are you seeing amazing amounts of evaporation?
If not, start checking over the tanks for other sources of lime. On my previous tank, I had coated gravel for many years. No CO2, low light, amazingly high pH (8.2 - 8.4) and ppm CA (as in the 200+ range beyond the edge of the test kit I had) and lots of algae. (Too bad I wasn't into Rift Lake cichlids..)
I set up the new tank, and started testing for KH & CH, and was shocked at the difference in pH as well.
Puzzling, why the old tank was consistently massively higher than the new one (before any CO2 added.)
Then I figured out the big difference was the old gravel.
Try putting a strong acid on some of that generic gravel (you might even see it with vinegar) and see if it's fizzing because it's limestone or other soluble limey rock, check any decorations etc. DOesn't help for the two tanks you mention that don't have the sand and gravel, though.
You might be able to use this as a pH buffer for your CO2 injection (as some of us throw bags of coral in our filters etc. to do, or else add powdered dolomite and baking soda) but it helps to know what it is, and how much of it there is.
Good luck hunting!

I have a flourite substrate with laterite and Fertiplant Plus
(see http://www.floridadriftwood.com/product.asp?0=242&1=255&3=766 for more
info on the latter), and our well water has a pH that ranges between 7.4 and
7.6.  I have a heck of a time keeping the pH below 8 in my tanks, though.  I
can keep it between 8 and 8.2 pretty easily with daily 20 - 25% water
changes, but getting below it is a challenge.  I've just gotten some Hagen
pelletized peat to try to help with this, and it's helping a little bit (I
need to figure out how much to use), but I'm still puzzled at the underlying
trend toward a high pH.  Two of my tanks have the flourite, laterite, and
Fertiplant Plus substrate, and one just has flourite, laterite, some gravel,
and some coarse sand, but all three tanks have this problem.  Any ideas?
The next time I set up a tank I think I want to change whatever it is that's
causing this upward pH creep.

Thank you so much for your informative explanation on the CO2 setup.  I
didn't realize how much I hadn't fully grasped about the setup until today -
I thought I had a better handle on it.  I really appreciate the help!


: -----Original Message-----
: From: aga-member-bounces@thekrib.com [mailto:aga-member-
: bounces@thekrib.com] On Behalf Of S. Hieber
: Sent: Saturday, February 19, 2005 5:30 PM
: To: Aquatic Gardeners Association Member Chat
: Subject: Re: [SPAM] [AGA-Member] pH shock - how to support recovery?
: : I'm not sure that I'm understanding you correctly. It
: sounds like you are saying that your regulator won't shut
: off the gas supply. IT's not meant to do that; only to drop
: down the pressure from the CO2 to something useful. In,
: fact as you get way down low on the output pressure side,
: the rgulator will be less stable and less accurate. That's
: normal unless the regulator is speically made to work at
: very very low pressures, like just 1 or 2 or 3 psi.
: However, Victors are generally expensive, high quality
: regulators.
: : The Valve on the CO2 tank should be the one used to shut
: off the CO2 completely.
: : Now if the problem is that the regulator won't regulate,
: won't maintain an even low side pressure down in the range
: you want, that's a diff issue. Whther the CO2 tank valve is
: opened jsut a tad or all the way, it presents the smae
: pressure tothe regulator. If open jsut a tad, then the tank
: won't be able to supply a very high volume of gas, but for
: aquaticf gardening purposes, only a very tiny volume of CO2
: is desired.
: : The regulator won't control the amount of gas flow; it only
: controls the pressure on the output side. At what pressure
: it holds the output (or low pressure side) depends on how
: far in or out the knob or adjustment screw is turned.
: : To control the amount of flow, you use a metering valve
: after the regulator. You have one of these in your setup?
: : The order is:
: : CO2 tank with valve -- the valve is used to turn on or off
: the supply of CO2 to the system, like when you are changing
: tanks for a refill, you want to shut off the CO2.
: : Regulator -- drops the pressure from the CO2 tank (usually
: about 650 to 850 psi) to a usable pressure (somewhere
: around 5-30 psi). If the regulator has two gauges on it,
: then one shows the pressure on the high side of the
: regualtor (i.e., the pressure from the CO2 tank) and the
: other the pressure on the low or output side of the
: regulator.
: : Metering valve -- controls the amount of CO2 that passes
: through the the system in a given period -- i.e., allows
: for a high or low volume of gas flow.
: : Solenoid (if you use one) -- an electrical low-pressure
: valve that shuts off/turns on the low side flow -- usually
: connected to a timer or a pH controller.
: : Is your problem that you can't control the amount of CO2
: that's going into your aquarium? If so then it's the
: metering valve that's probably at fault.
: : If you use the Milwaukee regulator, bubble counter,
: solenoid combo, I believe that combo doesn't have a
: metering valve so you need to add one to complete the
: system.
: : Trying to run without a metering valve is difficult becuase
: regulators tend not to be very stable at very low pressures
: and trying to limit the CO2 flow by output pressure alone
: generally requires very low pressure or an injector that
: present high resistance to gas flow. The eheim diffusers
: are pretty high resistance but you'll want a metering valve
: with one of those setups anyway to prevent rapid tank
: dumps.
: :

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