It can be quite frustrating when you arrive at home with your freshly bought CO2 system, connect everything up and the plants don't grow any better in the next few days than before. So should you be taking the CO2 system back and complaining?
No! If adding CO2 doesn't make your aquarium plants grow healthy and strong, then they are missing something else besides CO2. We just have to find out what it is.
Your aquarium plants need several factors to grow. If one of the factors is missing or is minimally present as a limiting factor, the plant will only grow as far as this limiting factor allows. The simplest example would be light: If you supply your plants with sufficient fertiliser, CO2 and trace elements, but only switch on the light for 2 hours, the plants will hardly grow due to lack of light. Exactly the same applies to ALL factors. So, for instance, a lack of potassium can limit growth.
How do you go about finding an existing deficiency? Let's start with the light: It’s a good idea to take a closer look at the spectrum of the light source, whether it is an LED or a fluorescent tube. The spectrum needs to cover all the spectral ranges and not have large gaps in its individual colour ranges. Then there are the nutrients essential for our aquatic plants. Besides the main nutrient CO2, it is nitrates and phosphates that plants need in sufficient quantities. It’s easy enough to simply add nitrates and phosphates to the water, but both substances will also serve as a food source for algae! So we have to be careful with their amount in the water. In normal community aquariums, nitrates and phosphates are present in abundance and we are more concerned with reducing their amount by using nitrate and phosphate removers. Only in aquascaping and very lightly stocked aquariums are there generally too few nitrates and phosphates and there we need to top up with special fertilisers (JBL ProScape NPK fertilisers). Finally, we have a tendency to overlook the issue of minerals and trace elements. This is the case both with human nutrition and with aquatic plants. The plants are in the same situation as we are: if we only eat our basic foodstuffs such as carbohydrates, fats and proteins, our diet will sooner or later kill us. We can' t live without minerals and vitamins. Our aquatic plants do not need vitamins, but they absolutely need minerals, which, however, must be added by the aquarist. It would take millions of years for enough minerals to dissolve from our decorative stones and the gravel in the water. Here we really have to invest a bit of money and buy a good fertiliser like JBL PROFLORA FERROPOL. If you keep really sensitive and demanding aquatic plants such as Rotala macranda, you cannot do without an additional daily fertiliser. The daily fertiliser supplies the water with minerals and trace elements that cannot be fertilised "in stock", as they would be oxidized by the oxygen in the water and would then no longer be available to the plants.
So getting back to the issue of CO2: It should now be clear why a CO2 fertilisation system is a huge step towards beautiful plant growth, but is never enough. Only when the factors light, nutrients, minerals and trace elements are taken into account - as well as CO2 - will plant growth be successful. But then it is guaranteed!
You can find more about CO2 fertilisation here: Fertilización de las plantas con CO2