75 or 90 for planted?
 

Hi Dustin,

A lot of this reiterates what Chuck states...

You're actually talking about 2 different things here. What happens in
a tank dump is that the regulator tries to equalize the pressure on
both sides of itself, thereby continuously adding co2 to the aquarium
at a rate faster than it can be used. The easiest way to avoid this is
to use a needle valve between the regulator and tank. I got the one
from Dave Gomberg (wcf.com) and I'm very pleased with it. Now with a
tank dump here's what happens. Co2 is added to the tank so fast that
most of it escapes to the atmosphere. With a tight fitting aquarium
cover the co2 will blanket the waters surface, and prohibit an oxygen
exchange. This is what kills the fish. There is no oxygen available at
the waters surface since it's all co2. I don't know for certain if
this phenomena will happen with a tank that doesn't have a cover on
it. The easiest way to avoid a tank dump is to use a needle valve and
watch the regulator pressure on the tank side (high gauge) of the
regulator. As long as there is co2 liquid in the pressurized tank your
pressure will remain constant at somewhere near 800 psi. When all of
the liquid is depleted the pressure will start to drop on the high
side of the regulator. It's going to take some time for it to get from
800 psi or so to 200-500 psi, where you're getting near the "failure"
point of the regulator. I've also read that if this "tank dump"
happens damage to the regulator is likely. IME with the "dose rate"
I'm using it takes about 2 weeks for the tank to get to 500 psi. At
that point I disconnect the regulator and the tank and I take a short
ride to the welding shop. The only way to get liquid from the
pressurized tank to your aquarium is if the pressurized tank has
liquid in it and it falls over. The way I prohibit this is to tie it
to the center brace in the tank stand.

I think the reference you're speaking of with liquid getting into the
aquarium has to do with the sugar/yeast method of generating carbon
dioxide. I'm completely green on that subject, and I'll leave that to
someone that knows what they're talking about.


On Thu, 2 Jan 2003 17:31:51 -0800, "Dustin"
wrote:

Alright,

By a tank dump then, you are talking about alot of co2 *gas form* comming
out all at once and sufficating the fish?

I thought you meant liquid comming through and contaminating the water. I
called the welding shop, where I bought the co2 tank, and they said the
liquid could only come out if there was a tub inside the tank, which is
normally only used for large tanks *50gal+* or Paint Ball Tanks.

Which needle valve do you prefer, or is there such a thing?

Thanks!

Dustin
"Chuck Gadd" wrote in message
.. .
On Thu, 2 Jan 2003 02:58:26 -0800, "Dustin"
wrote:

THanks for the input Cannibul, that I did buy that system. Wish I hadnt
know, maybe I can get a refund.... I dont like the idea of loosing all
the
fish...... was it because he didnt have a needle valve, or because the
product is junk?

The product is perfectly fine. The problem is that the system doesn't
use a needle valve.

But even without a needle valve, the system is SAFE, and works fine.
The issue is what is known as an "end of tank dump". Co2 regulators
are intended to operate with a tank pressure of 800-2000 psi (CO2
pressure will never get that high, it's usually around 800-1000psi).
On the regulator, the high pressure gauge is marked in red from
0-600psi. This is because, when the CO2 runs out, the tank pressure
drops down. The regulator is unable to properly regulate when the
tank pressure is very low. In theory, anything below 600psi is a
problem. In practice, I've run my regulator (from Dave Gomberg) down
to 300-400psi with no "dump". But in any case, once the pressure
drops below the regulators minimum, the regulator looses the ability
to regulate the output properly, and the output pressure will rise.

Since with the "high pressure system" the pressure directly controls
the bubble rate, this rising output pressure results in a CO2
overdose.

At the extreme end, the regulator can completely loose control when
the tank pressure drops very far. At that point, it would vent all
the remaining CO2 in a sudden burst.

For all of these cases, simply adding a needle valve will provide a
safety net.

But, if you keep an eye on the tank pressure, it's easy to notice
BEFORE the tank pressure drops very far. Unlike watching your car's
gas gauge, the CO2 pressure will remain constant (around 800-1000psi
depending on the temp) until the tank is 99% empty. When the CO2 tank
is filled, the CO2 is under pressure, and is in a liquid form. As
long as ANY liquid CO2 remains in the tank, the pressure stays at that
800-1000psi. Once all the liquid is gone, the pressure will start to
drop.

On my tank, with a fairly high CO2 flow rate, I would get about a week
from the time the pressure first started to drop, till it reached the
600psi mark. So even without a needle-valve, if you glance at the
CO2 pressure once every few days, you will see it in time to prevent a
problem.

On my system, with a needle-valve, I intentionally let the pressure
drop all the way down. I run the regulator pressure at about 6psi
normally, and then control the bubble rate with the needle-valve. I
usually have a bubble rate around 2-3 bubble per second. As the tank
pressure dropped below 300psi, the output pressure rose up slowly to
about 15-20psi. I never saw a true "end of tank dump" with a big
spike in output pressure. And the bubble rate (because of the needle
valve) didn't increase much, less than 1 extra bubble per second.

Possibly a bigger issue with the Dave Gomberg high pressure system, if
it's the same as when I bought mine several years ago, is that the
tiny little Eheim diffusor isn't very effective in large tanks. In my
75g, I was unable to get acceptable CO2 levels using it. I ditched
the eheim diffusor, added a needle-valve, and built my DIY reactor,
and I've been very happy ever since.


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

75 or 90 for planted?
 

On Sun, 05 Jan 2003 12:49:08 -0600, Joe Ferenchik
wrote:

exchange. This is what kills the fish. There is no oxygen available at
the waters surface since it's all co2. I don't know for certain if
this phenomena will happen with a tank that doesn't have a cover on

I've seen a CO2 overdose (not caused by end-of-tank dump, but rather
due to a faulty pH probe/controller), which killed a bunch of fish in
an open-top tank. The deaths were caused not by lack of O2, but
rather by the massive amount of CO2.

ride to the welding shop. The only way to get liquid from the
pressurized tank to your aquarium is if the pressurized tank has
liquid in it and it falls over.

Even then you probably wouldn't get liquid CO2 out. It would be
stopped by the regulator, but it might damage the regulator.


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

75 or 90 for planted?
 

Chuck,

Is your CO2 flowing at the same rate all the time? I seem to recall
sometime ago, you mentioned that you leave your CO2 going even at night. If
this is the case, how much PH fluctuation do you normally see during any
given 24 hour period?

I saw an article on your site regarding constructing a wet/dry filter. I
assume you use a wet/dry filter, right? Does this sort of filtration allow
you to more easily stabilize input and outgo of CO2 in the water? I wonder
if this makes CO2 injection without a controller easier.. what is your
feeling on this? If you were to use a different filter, like a canister
filter that is enclosed and therefore not amenable to CO2 dissipation, do
you think it would be more difficult to regulate CO2 (without a controller)?
Just curious.

I personally would have a much harder time maintaining conditions in my tank
without a controller, since I am not near my tank much during the week. A
controller has worked well for me for the past couple of years.

-Bruce Geist


"Chuck Gadd" wrote in message
...
On Sun, 05 Jan 2003 12:49:08 -0600, Joe Ferenchik
wrote:

exchange. This is what kills the fish. There is no oxygen available at
the waters surface since it's all co2. I don't know for certain if
this phenomena will happen with a tank that doesn't have a cover on

I've seen a CO2 overdose (not caused by end-of-tank dump, but rather
due to a faulty pH probe/controller), which killed a bunch of fish in
an open-top tank. The deaths were caused not by lack of O2, but
rather by the massive amount of CO2.

ride to the welding shop. The only way to get liquid from the
pressurized tank to your aquarium is if the pressurized tank has
liquid in it and it falls over.

Even then you probably wouldn't get liquid CO2 out. It would be
stopped by the regulator, but it might damage the regulator.


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

75 or 90 for planted?
 

On Thu, 9 Jan 2003 07:41:29 -0500, "Bruce Geist"
wrote:

controler. Are you able to set your flow rate and let it go for a while
without fear, or do your really need to check it often during a day? How

I haven't looked at or adjusted the bubble rate in at least several
months.

long does it take you to get re-set after swapping out your CO2 cylinder?

I don't change the needle-valve or regulator setting when swapping out
the cylinder, so it doesn't take any time to get it re-set.

Every week or so, I check the pH, and I glance in the CO2 reactor. If
the pH is out of line, or if the amount of CO2 swirling around in the
reactor doesn't look right, I might tweak the needle valve slightly.

that little bit of a swing without a controller. I think the best I ever
did was about .5 swing, which I thought might start killing fish

A pH swing won't kill fish. Extremely high CO2 levels might, but a
small pH variation due to CO2 levels won't effect fish. The cases
where pH changes can hurt the fish are when the different pH is due to
different levels of hardness.


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

75 or 90 for planted?
 

On Wed, 8 Jan 2003 19:27:01 -0500, "Bruce Geist"
wrote:
Is your CO2 flowing at the same rate all the time?

yes

sometime ago, you mentioned that you leave your CO2 going even at night. If
this is the case, how much PH fluctuation do you normally see during any
given 24 hour period?

6.8 during the day, 6.6 in the AM before the lights come on..

I saw an article on your site regarding constructing a wet/dry filter. I
assume you use a wet/dry filter, right? Does this sort of filtration allow
you to more easily stabilize input and outgo of CO2 in the water? I wonder
if this makes CO2 injection without a controller easier.. what is your

Possibly. In a tank with the absolute minimum CO2 loss, it's
reasonable to expect slightly higher CO2 accumulation during the
night.

I don't know that it's really necessary to maintain extremely stable
CO2 levels. In nature, it's common for nighttime CO2 levels to be
higher than daytime levels. This is a natural swing. In fact, this
natural CO2 swing might even be beneficial to plant growth. Here's a
study that found improved growth when CO2 levels were allowed to drift
higher at night:

http://www.co2science.org/journal/2002/v5n4b1.htm



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

75 or 90 for planted?
 

6.8 during the day, 6.6 in the AM before the lights come on..

My PH fluctuates from 6.65 to 6.75 with the controler-- which is really not
that much less variance than what you have been able to achieve without a
controler. Are you able to set your flow rate and let it go for a while
without fear, or do your really need to check it often during a day? How
long does it take you to get re-set after swapping out your CO2 cylinder?

Possibly. In a tank with the absolute minimum CO2 loss, it's
reasonable to expect slightly higher CO2 accumulation during the
night.

I don't know that it's really necessary to maintain extremely stable
CO2 levels. In nature, it's common for nighttime CO2 levels to be
higher than daytime levels. This is a natural swing. In fact, this
natural CO2 swing might even be beneficial to plant growth. Here's a
study that found improved growth when CO2 levels were allowed to drift
higher at night:

http://www.co2science.org/journal/2002/v5n4b1.htm

Interesting article. Thanks. (I am amazed there is journal called "CO2
Science", glad to know about it.)

A .2 variation is nothing! I don't know that I ever succeeded in getting
that little bit of a swing without a controller. I think the best I ever
did was about .5 swing, which I thought might start killing fish (especially
since that is the BEST I ever did).

Well if I ever re-do my CO2 system, I may try getting a wet/dry filter and
(probably more importantly) a better CO2 regulator/needle valve. I have
trouble at times getting a consistent flow through my regulator/needle valve
combination, particularly after I change the CO2 tank -Bruce Geist

75 or 90 for planted?
 

you might want to think about acryllic tanks for this size, it will make
them far lighter, and the rounded edges look nice
"Dustin" wrote in message
...
Thanks for the input you two :)

I bought a 125 gallon today on sale at the lfs, I got a better discount
since I am friends with the manager, 599.00 Im guessing that is a good
price :)

Any suggestions for lighting this for plant growth? :)
Thanks!
"Bruce Geist" wrote in message
...
I have a 135 gallon tank that is 24 inches high. Leigh, as usual, gives
excellent adivce. She (I hope you are a she Leigh-- if not then I
appologise in advance..) is right about the light, though I find that
even
though its tougher to light the bottom of the tank, 25 inches is not
insurmoutable-- especially if you are going to terrace. In addition, I
personally think that less than 24 inches looks a little funny with a
canopy. You may (or may not) choose to place a canopy over the top of
the
tank-- but assess how you think it may look with the shallower tank in
the
event you do want a canopy. Keep in mind also that there may be plants
that
you want to keep that get tall. It may be nice to have certain sections
of
the tank that are deeper than others. Just keep in mind that you may
have
trouble with high light plants in the deep areas.

Certainly the "long arms" issue is real also. If you are a small
person,
then you may want to avoid buying a tank that is too deep for you to
reach
into. I know my wife would have a hard time reaching the bottom of my
135
gallon tank. I do not have a problem with this depth-- though any
deeper
would become a hassel.

In summay, my cutoff would be about 24 inches-- not 21 inches. 25
inches
may be problematic, but its worthy of careful consideration.

For what its worth, that is my 2 cents. -Bruce Geist

LeighMo wrote in message
...
Id like a 75 or 90 from all-glass. Which of these is better for the
planted
aquarium in yoru optinion, and where is the best tank for my buck?
any
mail
orders, or something to that effect?

Ordinarily, bigger is better, but for a planted tank, I'd go with the
75
gallon.
The 90 and the 75 have the same "footprint." The only difference is
the
75 is
21" high, and the 90 is just over 25" high. A planted tank deeper
than
24" can
be difficult. That depth is hard to light adequately. (You wouldn't
think
only a few inches would make a difference, but it does, because light
intensity
falls exponentially with distance.)

A planted tank also requires constant maintenance, and if the tank is
that
deep, it will be difficult (unless you have really long arms!). I've
heard of
people who accidentally poisoned all their fish, because they reached
into
a
deep tank without showering first, and their underarm deodorant got
into
the
tank.

As for price...mail order for a tank this size is not economical. The
shipping
will kill you. Your best bet is probably to order it from a chain
like
PetCo.
The big chains use tanks as "loss leaders," selling them at a loss in
hopes
that they'll make it up by selling you fish, accessories, etc. Call
around
your LFSs and ask, but IME, the small local shops will all charge
hundreds
of
dollars more than the big chains. The local shops around here all
wanted
$700
to $800 for an All-Glass 75 gallon economy tank and stand. PetCo
asked
$325
for tank, stand, and glass canopy top.


Leigh

http://www.fortunecity.com/lavender/halloween/881/