That is because they cannot measure the CO2 accurately, not that the dissolved CO2 is in fact at that level.
Back in my lab days, where we used used gases (CO2/O2/N2) to control culture pH and/or ORP, measuring CO2 accurately was a practical impossibilty. And we had full analyses of the culture media, so knew exactly what was in the vessels. If we could not do it will hundreds of thousands of dollars in instrumentation and the FDA looking over our shoulders, I don't see accurate CO2 determinations in the hobby world being a realistic expectation.
We are left with TLAR (that looks about right) and very rough estimates. This is not that bad a thing. Planted tanks are biologically and biochemically complex, but are not rocket science. Approximations and compensations are not only acceptable, they can be preferable in the real world.
Back in my lab days, where we used used gases (CO2/O2/N2) to control culture pH and/or ORP, measuring CO2 accurately was a practical impossibilty. And we had full analyses of the culture media, so knew exactly what was in the vessels. If we could not do it will hundreds of thousands of dollars in instrumentation and the FDA looking over our shoulders, I don't see accurate CO2 determinations in the hobby world being a realistic expectation.
We are left with TLAR (that looks about right) and very rough estimates. This is not that bad a thing. Planted tanks are biologically and biochemically complex, but are not rocket science. Approximations and compensations are not only acceptable, they can be preferable in the real world.
