Re: [SPAM] [AGA-Member] pH shock - how to support recovery?

["S. Hieber" <shieber@yahoo.com>]

A couple of points that might (?)_ be helpful:

A regulator made for CO2 usually will be capable of high
side gas pressures of 2000 or even 3000 psi. CO2 tanks are
usually specified for around 1800 psi, or 2000 psi, or more
depending under whcih DOT regulation specification it was
certified. A CO2 tank in the USA is allowed under DOT
regulations to be filled to a specified weight (which is
actually stamped on the tank along with the Tare weight).
Contact me offline if you wnat to know how to translate
what's stamped on the tank. 

The DOT specified net weight that a CO2 tank can hold
results in a tank pressure at normal room temps of about
650-850 psi.  If the gas shop overfilled your CO2 tank
enough to break a CO2 regulator, they must be ignoring the
DOT regs and your safety as well since they would probably
have to be filling the tank to more than 2000 psi. If
that's the case, consider finding another gas shop.

Diff regulators will be designed for diff optimum operating
low-side pressures. I have a Scott's 2-stage regulator
that's stable down to just a few PSI. But it's a very
expensive regulator (about $400 new) that I picked up used
just to try it. Some regulators have an optimum low side
range above 10 psi.

I think most of the CO2 regulators for the hobbyists are
good down to about 10 psi. I can find your model in the
Victor price list but not the specs -- but I suspect the
regulator can withstand high side operating pressures of at
least 2000 and probably 3000 psi. 

*****
Adjusting regulator outlet pressure. Unless the outlet line
is partly open then adjusting the regulator to a lower
outlet pressure will not show results on the low side
pressure gauge. The pressure can't drop until some of the
gas in the low side of the system leaves. One way to see
fast results is to adjust the regulator lower and then open
the metering valve until the regulator low side gauge stops
lowering. The same problem doesn't occur for adjsuting the
regulator higher -- in that case, more gas is forced into
the low side until the set pressure is reached.
*****
I'm not familiar with NoShok's line of needle valves or
find any cv specs on their website, so I can't comment on
their performance. Generally, diff valves will be usefull
for diff ranges of gas flow and for aquatic gardening,
we're interested in very tiny rates of flow. The lower the
volume of gas flow for which a valve is intended, the more
likely that it will be easy to make subtle adjustments. The
others, intended for large flow rates, will change the
aquatic gardener's CO2 flow tremendously if one just barely
turns the knob at at all. That's an inconvenience and not a
fatal flaw. I prefer the expensive Swagelok B-SS4, which
allows one to make large turns of the knob for very small
changes in gas flow -- but most folks are content with
cheaper valves.
***************
If your regulator can't maintain a low side pressure any
lower than about 25 psi, then you will need a needle valve
that is capable of adjusting very finely when presnted with
relatively high pressure. The higher the pressure, the
smaller the valve opening the smaller the changes in valve
opening required to make small adjustments.

a few more comments below. . .

sh
--- Heather J Gladney <hgladney@comcast.net> wrote:


> A No-Shok needle valve follows the solenoid.  Is this
> sufficient as a 
> metering valve?
> Today I put the Victor regulator on, with no further
> equipment, to see 
> if it was working.  It does bring the pressure down to
> about 25-30 psi 
> but no lower.  That alarmed me enought hat I have not
> tried to put the 
> rest of the equipment on.  From the regulator, the line
> goes to a 
> solenoid (which goes into a Milwaukee pH meter) then to
> the No-Shok 
> needle valve.
> 

> It had a needle valve on it. The old setup was one of
> those 
> locked-together pieces with a Milwaukee regulator to
> solenoid to needle 
> valve into bubble-counter, the sort of setup commonly
> sold on aquarium 
> websites.  When the overfilled CO2 tank blew out that
> regulator, and 
> then the overflow wouldn't reseat, after many adventures,
> I got the 
> Victor.  THe Milwaukee setup took some tweaking to get
> the flow where I 
> wanted it, but once I got it set up it was fine.  I ust
> figure it'd be 
> nice to have a regulator that doesn't die when the
> overflow valve gets hit.

The rebuild kit for your medalist regulator is listed at
$37 retail and probably is available for less. The
"overflow" is basically a spring and disk and replaceable
if it malfunctions.

> I'd still like a bubble counter screwed inline like that,
> but apparently 
> the Milwaukee setup uses some wierd French threading that
> the gas store 
> guys had never seen before, and it'd be amusing trying to
> get adapters.  
> The other buibble counters I've found have been the kind
> you put into 
> the flexible airline, not into the needle valve
> I haven't bothered to hunt down further, as part of the
> tank diffusion 
> setup has one of those yeast-bottle bubble ladders, which
> I figure will 
> give me a rough idea a little sooner than the pH meter.

You can make a bubble counter out of pill bottle and some
rigid airline tubing and some epoxy. The
connect-to-airline-tubing ones work well. Bubble counters
are a convenience and luxury, not necessary nor a good way
to judge CO2 levels. All the less important ;if you have a
pH controller and solenoid. Use pH, KH, CO2 table for
judging CO2 levels. The Milwaukee pH controller, which it
appears you are using, is very reliable. If you know your
KH and desired CO2 level, you can set the Milwaukee and
count on it to maintain the pH within 0.1 unit higher and
0.1 unit lower, which is the range for it's trigger points.

 
> Thanks very much for your help!

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