Inches. -. A shoe size is a numerical indication of the fitting size of a shoe for a person. Several different shoe-size systems are still used today worldwide. In some regions, it is even customary to use different shoe-size systems for different types of shoes (e.g., men's, women's, children's, sport or safety shoes).
Types of Algae. Brown Algae (Diatoms)  This is the first type of algae that begins growing in a new aquarium. It usually grows on the gravel and glass. Unlike other types of algae, this type requires silicates in order to grow. By increasing light levels, this type of algae can be replaced by the more beneficial green algae. Brown algae can easily be scraped off the glass.
There are 7 main types of algae (but more do exist) that aquariums can have. Brown algae. Brown Algae. This will probably be the first type of algae any one will encounter in the aquarium and could appear from early on and will normally disappear when the tank stabilises and becomes more mature. Brown algae could be in the form of a fluff like or spot appearance on plant leaves, rocks, glass, substrate or decorations.