I am wanting to do away with my plants only tank, and want to put all the
plants in the planted fish tank along with the c02. My concern is for the
fish and setting the co2. In my plants only tank I never could get a good
reading for co2 and after fiddling for some months finally gave up and just
set the bubble rate at a reasonable rate and slowly adjusted until I got a
reasonable plant growth. To heck with what the ph and co2 concentration was.
I would like to use this approach on the planted fish tank but don't want to
cause any harm to the fishies. What do you think? Thanks.
--
Paul

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

You could probably do that even with fish if you were very conservative with
the CO2 bubble rate. that would be the key at any rate. making sure you had
lots of bogwood to buffer the water would another and turning off the CO2 at
night.
remove nospam from e-mail to send to me, I grow trees in aquariums like bonsai.
I breed dwarf crayfish, great for planted community tanks. If you can get me a
shovelnose sturgeon fingerling (Scaphirhynchus platorynchus) no wild caught
please, contact me

You could probably do that even with fish if you were very conservative with
the CO2 bubble rate. that would be the key at any rate. making sure you had
lots of bogwood to buffer the water would another and turning off the CO2 at
night.
remove nospam from e-mail to send to me, I grow trees in aquariums like bonsai.
I breed dwarf crayfish, great for planted community tanks. If you can get me a
shovelnose sturgeon fingerling (Scaphirhynchus platorynchus) no wild caught
please, contact me

As far as fish and CO2 are concerned....

Don't worry about the fish unless they are gasping at the surface.

As for the CO2...

a) I would definately have a night shutoff valve if your CO2 is injected. It
does 2 things. Saves on CO2 and allows the oxygen to build up at night when
plants respire CO2 (hence you don't want too much in there). Pumps put
oxygen into water by creating a moving surface whereby gaseous exchange
takes place. This exchange also loses CO2 to the atmosphere.
b) Whatever your pH is, the CO2 will lower it to a certain degree anyway and
I would bubble enough in so that the fish are not gasping at the surface.
While at the same time making sure the plants are doing very well. This is
just being very sensible.
c) Ensure that the more CO2 that you inject actually gets absorbed into the
water - its no good bubbling it in for it to reach the surface and escape.
d) No matter how much CO2 you inject if the surface water is alive with
bubbles, either from a highly placed venturi jet or a via injected airline,
then this will decrease the CO2 as it is lost faster when the surface is
highly agitated. The trick is to have a smooth water surface - but one which
is always moving. Therefore, being conservative with the CO2 while agitating
the surface too much - will be next to useless.
c) As for the bogwood - I am not convinced that this will do any good at
all - I believe that buffering (in an attempt to lower the pH) is best
achieved with peat in the external filter. Yes bogwood will have an effect
but only if the tanins in it are new and are being leached into the water -
old (already leached) bogwood will do nothing. But don't go out of your way
to lower the pH too much see what happens with the CO2 that is being
injected.

I am running a JBL injector with a 4 bubbles/second rate in a 250Litre tank.
The injector is on for 11 hours (as are the main lights). The spiral
diffuser is slightly too small as the bubbles are still visible when they
reach the top...and then they just go over the edge. My JBL CO2 chemical
sensor says that its OK for a pH of 7, which is placed at the opposite
corner to the diffuser. Hence, I would expect a gradient across the tank.

Hope this all helps.

Martin

As far as fish and CO2 are concerned....

Don't worry about the fish unless they are gasping at the surface.

As for the CO2...

a) I would definately have a night shutoff valve if your CO2 is injected. It
does 2 things. Saves on CO2 and allows the oxygen to build up at night when
plants respire CO2 (hence you don't want too much in there). Pumps put
oxygen into water by creating a moving surface whereby gaseous exchange
takes place. This exchange also loses CO2 to the atmosphere.
b) Whatever your pH is, the CO2 will lower it to a certain degree anyway and
I would bubble enough in so that the fish are not gasping at the surface.
While at the same time making sure the plants are doing very well. This is
just being very sensible.
c) Ensure that the more CO2 that you inject actually gets absorbed into the
water - its no good bubbling it in for it to reach the surface and escape.
d) No matter how much CO2 you inject if the surface water is alive with
bubbles, either from a highly placed venturi jet or a via injected airline,
then this will decrease the CO2 as it is lost faster when the surface is
highly agitated. The trick is to have a smooth water surface - but one which
is always moving. Therefore, being conservative with the CO2 while agitating
the surface too much - will be next to useless.
c) As for the bogwood - I am not convinced that this will do any good at
all - I believe that buffering (in an attempt to lower the pH) is best
achieved with peat in the external filter. Yes bogwood will have an effect
but only if the tanins in it are new and are being leached into the water -
old (already leached) bogwood will do nothing. But don't go out of your way
to lower the pH too much see what happens with the CO2 that is being
injected.

I am running a JBL injector with a 4 bubbles/second rate in a 250Litre tank.
The injector is on for 11 hours (as are the main lights). The spiral
diffuser is slightly too small as the bubbles are still visible when they
reach the top...and then they just go over the edge. My JBL CO2 chemical
sensor says that its OK for a pH of 7, which is placed at the opposite
corner to the diffuser. Hence, I would expect a gradient across the tank.

Hope this all helps.

Martin