Pollen Glass used in CO2 System realizes a high CO2 diffusion efficiency by producing and supplying fine bubbles of CO2 to aquarium. However, Pollen Glass may not display its full performance depending on where it is installed and how it is used. The Nature Aquarium Notes of this issue discusses the effective installation of Pollen Glass.



■Effectiveness of CO2 supply

There are certain requirements for growing healthy plants in an aquarium. Along with light intensity, water quality and water temperature, adequate CO2 concentration is also one of such requirements. Aquatic plants perform photosynthesis by catching sunlight on their leaves as well as stems and produce organic components that are essential for the growth and respiration. In this process, CO2 serves as the source of organic compounds. Aquatic plants that perform photosynthesis underwater absorb CO2 dissolved in water through their leaf surface. CO2 exists in atmosphere at a concentration of around 0.03-0.04% and easily dissolves in water. In natural aquatic environments, CO2 is always supplied via CO2 dissolved in water through water surface and CO2 produced by fish and other aquatic organisms. On the other hand, an aquarium having a limited space and number of fish often faces chronically insufficient supply of CO2 as compared with the CO2 amount taken in by aquatic plants. Insufficient CO2 constrains photosynthesis and hinders the growth of aquatic plants. It also affects the water quality and the organisms other than plants within the aquarium. Aquatic plants release oxygen as a by-product of photosynthesis, which will be used by fish, shrimp and microorganisms for respiration. If photosynthesis of aquatic plants is hindered, the oxygen supply will be insufficient and can cause a lack of oxygen in the aquarium. To overcome this problem, CO2 supply to an aquarium is an effective solution.




■ Features of Pollen Glass

Among several ways to supply CO2 to an aquarium, the most efficient and reasonable approach is the supply of CO2 using a cartridge filled with liquefied carbon dioxide. In fact, most of Nature Aquariums use this method. The CO2 supply uses Pollen Glass as a CO2 diffuser that produces CO2 fine bubbles to be dissolved in water. Pollen Glass is entirely made of glass including its white-color diffusion filter. This diffusion filter is very fine and CO2 flowing through it will turn into fine bubbles. CO2 basically dissolves into water easily, but the dissolution is further enhanced if CO2 is made into the form of fine bubbles using Pollen Glass. The Pollen Glass Series offers many types of models having different designs and diffusion filter sizes to cater to different tank sizes and preference of aquarists. The most basic Pollen Glass is designed for 60cm aquarium tank while Pollen Glass Large and Pollen Glass Beetle cater to larger aquariums. Meanwhile, Pollen Glass TYPE-2, Pollen Glass TYPE-3 and New Pollen Glass have the same size and CO2 diffusion efficiency as Pollen Glass but come in different shapes. You can choose these products according to your design preference.





■ Effective installation of Pollen Glass

Once you have chosen a Pollen Glass having your preferred shape and the suitable size for your aquarium, the next step is to connect the CO2 system and install it onto the tank. The key in this step is the depth of the location where Pollen Glass is installed. If Pollen Glass is installed too close to the water surface, the CO2 bubbles from Pollen Glass reach the water surface before they adequately dissolve in water and a high CO2 diffusion efficiency cannot be expected. On the other hand, if Pollen Glass having a silicon tube on the bottom is installed in a location very near the substrate, the tube easily bends. Also, Pollen Glass does not look good due to imbalanced position if it is located near the bottom of the tank. Pollen Glass provides a balanced look and high CO2 diffusion efficiency if it is installed at the middle level of the water depth. Some Pollen Glass products come with dedicated Joint Glass for sophisticated installation on a 60cm tank. As an additional note, the longer CO2 bubbles remain in water, the higher CO2 diffusion efficiency will be. In view of this, it is recommended to install Pollen Glass in an open space with water flow rather than in a location surrounded by lush aquatic plants where water is stagnant.




A: Joint Glass JG-007+Pollen Glass TYPE-2 (or Pollen Glass)



B: Joint Glass JG-008+Pollen Glass Large (or Pollen Glass TYPE-3/Pollen Glass Beetle)


Joint Glass is designed for use with major Pollen Glass Series products. The use of Joint Glass prevents bending of silicon tube and ensures the optimal installation position of Pollen Glass.





Can I use Pollen Glass for AIR instead of Pollen Glass for CO2 supply?



Pollen Glass and Pollen Glass for AIR have the same look but come in different specifications of the diffusion filter. The diffusion filter of Pollen Glass is a very fine glass filter and requires a relatively high pressure to produce fine CO2 bubbles. In contrast, Pollen Glass for AIR designed for aeration has a rough glass filter so that air bubbles are produced even when a low-pressure air pump is used. If Pollen Glass for AIR is used for CO2 supply, it produces large CO2 bubbles and results in extremely poor efficiency of CO2 supply. For this reason, Pollen Glass for AIR cannot be used for CO2 supply.



Pollen Glass AIR is designed to produce large bubbles even at a low pressure to ensure effective aeration.







The diffusion filter of my Pollen Glass got dirty. How can I clean it?



Just as other ADA glassware, Pollen Glass is cleaned by soaking it in Superge, a glassware cleaning agent. Even if the diffusion filter of Pollen Glass has turned green due to algae, it can be clean by soaking it in Clean Bottle filled with Superge solution for about an hour. In the event where the diffusion filter is stained brown even after cleaning with Superge, rinse the filter well with water and then soak it in vinegar in a glass or other types of container. Thoroughly rinse off the vinegar with tap water before reattaching Pollen Glass to the aquarium tank.



Diffusion filter





Clean Pollen Glass by soaking in glassware cleaning agent Superge in Clean Bottle.








Do I need to use CO2 Bubble Counter when supplying CO2 with Pollen Glass?



Just with a CO2 diffuser Pollen Glass, you will not know how much CO2 is supplied to the aquarium. That is why CO2 Bubble Counter is installed to measure the amount of CO2 supplied. For example, the standard CO2 amount for 60cm tank is 1 bubble per second during the initial setup period. If CO2 Bubble Counter is installed to the tank, you will quickly find the excessive or insufficient CO2 supply. If you have a large aquarium tank, use CO2 Beetle Counter together with Pollen Glass Beetle designed for a large amount of CO2 supply.




In CO2 Beetle Counter, CO2 bubbles rise in spirals to allow the user to count CO2 bubbles easily even when a large amount of CO2 is supplied.




(From Aqua Journal #253)