how to induce CO2 in low water level tank?

[sushant]

External CO2 reactor will be best for dispense CO2 in the tank.

this would require an additional pump, right?
my internal filter has no connection for a hose.

if your filter is the one having slit type outlet then you will definitely require another pump for the reactor.

[marsaiko]

no, i want CO2...so i can avoid the daily routine.
bell is a good idea and works quite well...reminds me about my old bio-co2 days . forgot about it completely.

Yes, that old pretty days... surely was effective.
New age blokes really miss that fun-experimental times.

Pic below- always helped near 100% solubility... only at low BPS though... but that should do for a nano at 1bps /50bpm