[RainSong]

I have a 90 gallon heavily planted tank with pressurized CO2. I am trying to dial in my CO2 to fight algae. I keep dialing up the CO2 but back it down because of the following:

When the lights/CO2 first come on, ALL my fish start rapidly opening and closing their mouths. The drop checker is green. I hate the idea of hurting my fish and end up turning down the CO2.

Is the mouth-open-close-thing a "normal" behavior when lights come on or is it related to too much CO2?

 

[Patriot]

I have a 90 gallon heavily planted tank with pressurized CO2. I am trying to dial in my CO2 to fight algae. I keep dialing up the CO2 but back it down because of the following:

When the lights/CO2 first come on, ALL my fish start rapidly opening and closing their mouths. The drop checker is green. I hate the idea of hurting my fish and end up turning down the CO2.

Is the mouth-open-close-thing a "normal" behavior when lights come on or is it related to too much CO2?

Heavy breathing maybe. i would guess not enough Oxygen. how much disturbance does your water surface have?

 

[RainSong]

One of my filter returns is at the surface pointing up and creates a steady ripple.

 

[lauraleellbp]

Too much CO2.

You might try adjusting the CO2 timer to not come on till an hour after the lights.

 

[Kibblemania1414]

put an airstone in...

 

[shrimpNewbie]

are your fish gasping at the surface? if they are then it isn't a co2 issue =p

 

[roadmaster]

Reduce lighting,and CO2/nutrient's will not be in such demand.This could slow down algae and perhaps help fishes while still allowing more growth from plant's than NON CO2 tank.
See that plant's aren't nutrient limited which might be if lighting and CO2 are plenty.
Plenty of flow to disperse nutrient's and CO2.
Maybe something to aerate the tank of an evening when CO2 is off?