midpost

On Sun, 25 May 2003 11:18:19 +0100, Skunky
wrote:

OK, I have now managed to set up my pressurized set up. I am using a
twin gauge Deltec regulator with needle valve, an Aquamedic bubble
counter, with a 14lb bottle, feeding the CO2 directly to the intake of
my Eheim Pro II 2028.

Firstly, I have set the regulator pressure @ 1 bar, is this enough?

Bubble rate is 1 bubble per second.

a measure of pH and hardness kh on a co2 graph will show you where
your concentration in mg/l is (see co2 links)

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm my favorite..


Now to my main worry, TANK DUMPS!!!

Tank dumps are essentially alleviated/eliminated with the use of a
metering device (needle valve). This is because no matter what happens
at the regulator it's the needle valve that is regulating the flow
into your tank. The regulator is just setting your output pressure to
the needle valve.

I have read a few horror stories about bottles dumping their last load
of CO2 into the tank when they are coming to the end, killing all the
inhabitants. Can this catastrophy be avoided and if so, how?

Yes it can and it appears that you have all of the necessary hardware
in place to curb this malady. Essentially what happens is that the
cylinder dumps the remaining gas in the tank. The excess co2 blankets
the surface of the aquarium (especially those with a tight fitting
lid) thereby prohibiting an oxygen gas exchange at the waters surface.
This happens because there is nothing to meter the gas into the
aquarium.

Now IME I've got a needle valve regulating the flow to my diy reactor
and I've had my cylinder at less than 50 pounds pressure before I've
cut it loose and taken it in for an exchange. I have had no ill
effects in letting the cylinder go this low. It takes quite a bit of
time once the pressure gauge starts to drop (no more liquid in the
cylinder) to where you'd get to the panic point anyway. I'd think that
most people give their cylinder gauges a daily glance while they're
checking the operation of everything else. If you're a paranoid sort
you can also valve the cylinder out if you think it's gonna dump. The
regulators high/low side and the line to the needle valve will stay
charged for quite a bit of time (depending on your flow rate). You
can repeat this line charging process till you have the time to go get
an exchange cylinder. hth

Many thanx for your much needed advice!

snip