sera guide - Marine aquariums

46 The oceans represent the most stable eco- logical system on earth. The ocean inhabi- tants have adapted to the constant physical and chemical parameters over millions of years. As these parameters vary only slightly in nature, most of the ocean inhabitants are much less adaptable than freshwater inhab- itants. Because of this, the aquarium water must provide stable conditions without dras- tic fluctuations. pH value The pH value describes whether the water reacts acidic (pH below 7), neutral (pH = 7) or alkaline (pH above 7). The pH value in nat- ural marine water is slightly alkaline (pH 8 to 8.5). The pH in an aquarium is lower in the morn- ing than in the evening. This is due to the fact that during the day carbon dioxide (CO2) is consumed by the algae. As a result of the consumption of carbonic acid, the pH value will rise during the day. The pH value of the aquarium water should be checked regularly. The sera pH-Test allows easy monitoring of the pH value. Use sera KH/pH-plus for increasing the pH value. Due to their high CO2 requirements, the pH value may rise over 8.5 if you keep plenty of macro algae (Caulerpa, Halimeda etc.). 9.4 Monitoring and adjusting pH value, carbonate hardness and carbon dioxide pH acidic neutral alkaline 5 6 7 8 9 10 11 7 8 8,5 freshwater marine water Caulerpa