Homemade, semi-pro or pressurized CO2: which suits your planted tank?

Choosing a CO2 system is one of the first hard decisions when setting up a planted aquarium, and I found a guide that sums it up pretty well. It lays out three levels: homemade, semi-professional and professional.

Homemade, with yeast and sugar or with citric acid and baking soda, is cheap and easy to put together, which is why it is the most common choice for beginners. Its drawback is that it cannot be turned off before the photoperiod ends, so it also runs at night, when plants are not using it. The semi-professional setup adds a solenoid valve, a timer and a bubble counter, so it switches on and off by itself and the gas lasts almost twice as long, although you still have to remake the mix every time it runs out. The pressurized system is the safest and most automated, and depending on tank size it can last close to a year, but its cost is high, so it is not the best option for someone just starting out.

What caught my attention most is the part about "liquid CO2". According to the guide, these products contain glutaraldehyde, and the bacteria in the filter and substrate break it down, releasing very little organic carbon, between 5 and 10 percent of what a real gas system would give. Its real effect is that of an algaecide, useful for localized applications with a syringe on algae such as brush algae or staghorn algae.

My take: starting with something simple and saving up for a pressurized system seems like a sensible path, and being wary of easy promises.

Source: Acuarios Plantados