for the past few months I have struggled to maintain the proper CO2 balance. I have several CO2 readers in my tank and these barely turn green despite a large dose of CO2 (3+ bubbles per sec). My plants are doing OK, but not great. I see BBA growth in some areas (corners and driftwood). Anything that requires CO2 fertilization is doing poorly.
I wonder what might be the factor for this change in the balance in the last 6 months.
Here are the details of my tank:
1.- 180 gallons with 2 overflows.
2.- Sump/Refugium with 1200GPH pond master pump, net flow of ~500GPH.
3.- Pressurized CO2 cilinder and regulator.
4.- pH controller, CO2 in-line reactor using a pond master 700GPH pump, inlet and outlet inside sump tank.
5.- Parameter are set at GH 5, KH 4 and pH of 6 to 6.1.
CO2 is consumed at a faster rate than before, but I cannot find to get the right balance.
the tank consumes about a 10lb CO2 cilinder in about 6 weeks. I found this rate extremely high compared to past experiences.
Should I restrict the flow of the sump pumps to avoid surface gas exchange?
Is the carbonate hardness to low? How do I increase the dissolved CO2 without having to decrease pH further down?
Is the rate of consumption too high?
Any ideas are welcome.