X3NiTH
Member
- Joined
- 13 Apr 2014
- Messages
- 1,647
In the above instance two pH controllers were being used, one controlled CO2 and the other Air. One of the controllers could be set to reverse operation ie ‘turn on power’ when a set pH point was reached. The CO2 was dialled in so it never reached the set point to turn off the gas so it flowed continuously and evenly (traditional on off with a CO2 controller if graphed will show a sawtooth pattern of on off cycles, some may constitute this as instability) and only fluctuated if the controller controlling an air pump to create disturbance off-gassing a little CO2 was triggered.
The above was an experiment, I only run a single controller now. I always switch off the gas overnight but I feel it would be an unnecessary risk running CO2 24/7 if not on a controller because if you are aiming for a lime green/yellow drop checker to maximise plant growth and your tank occupants are near the cusp off toleration to the current levels but behaving normally, when plants start respiring in the dark period they may release enough CO2 and uptake of O2 to go beyond the toleration capacity of the animals and they will suffer stress from hypercapnia or at the worst asphyxiation.
I’m super cautious now running CO2 using any modality and especially controllers having lost an entire tank of inhabitants to fitting to the CO2 controlling controller a brand new calibrated pH probe that when CO2 came on in the morning (the morning after fitment and calibration outside a CO2 controlling period) read counter to the increasing acidity in the tank and never reached the set point to switch off CO2, kept pumping it in, came home to the gas still running, the controller reading somewhere between ph8 and 9 and the entirety of the tank inhabitants floating motionless on the surface, utterly devastating.
:-/
