Fish Gasping

scottward

Guru Class Expert
Oct 26, 2007
958
10
18
Brisbane, Australia
Hi,

Just repeating what I wrote in an earlier thread; I have a 100g tank, AM1000 + powerhead misting CO2 through a spray bar into the thickest parts of my planted tank.

CO2 comes on at 1pm and goes off at 11pm.
Lights come on at 2pm and go off at 12am.

I have been slowly tweaking my CO2.

At about 9pm, my fish start heading for the surface.

I understand that plants do most of their growing (i.e. CO2 utilisation) during the first 8-9 hours of the photoperiod. So, this seems to coincide with when my fish start gasping. Am I right to assume that my CO2 levels are probably pretty good between 1pm and 9pm, and then simply start to climb into the danger zone once plant utilisation slows down at 9pm?

I can either dial the CO2 down slightly, or, increase surface turbulence. I'm leaning towards the former as I don't want to waste CO2.

My tank is very understocked, by the way, so it can't be an oxygen shortage.

Scott.
 

shoggoth43

Lifetime Charter Member
Lifetime Member
Jan 15, 2009
1,092
11
38
Why not simply use a second time on the CO2 so you can have it shut off ~9 or so? Chances are the tank will be outgassed of CO2 within 30 minutes or less unless you have gone to some lengths to minimize all surface turbulence.

-
S
 

scottward

Guru Class Expert
Oct 26, 2007
958
10
18
Brisbane, Australia
Hi Shoggoth43,

I do use a second timer for the CO2 (1 timer for the lights, seperate timer for the CO2).

I could change the timer for the CO2 to turn it off at 9pm quite easily. I just wanted to check my assumptions first, before I go ahead and do this.

Scott.
 

MarkMc

Junior Poster
May 4, 2007
8
0
1
This is what I do. One hour before lights on-CO2 on-one hour before lights off-CO2 off. Couple of hours later an air stone comes on and runs for a few hours. 8 hour photoperiod.