Can you return the unit? Seriously, these are junk. They cost as much as a good pressurized
CO2 system for the initial startup, but then about every 2-4 months you'll have to spend $40 on a new carbon block. So another $120 a year on carbon, vs. $10-$20 a year for a
CO2 cylinder fill.
Carbo+ uses the carbonate hardness in your water, and breaks it down into the
CO2 your plants want. However it doesn't do this very efficiently, so it'll never really compare to a pressurized
CO2 system.
Furthermore, the softer your tank water, the less
CO2 it can create, and the more quickly it'll consume all your Kh, leaving you with little buffering capacity, and thus open to wild pH swings.
Lastly, it takes up more room inside the aquarium than a
CO2 gas diffuser.
Carbo+ is not exactly low-maintenance either...scale will build up on the metal sleeve that holds the carbon block, reducing it's effectiveness. its hard to clean, and lots of people tend to just replace the sleeve annually, which is another $30 I think.
As I said, if you can, return it, and re-think this whole
CO2 thing. If it's already in the tank...good luck.
