sera guide - Marine aquariums

43 ++ Calcium hydrogen carbonate Acidic or alkaline influences may strongly alter the pH value of the aquarium water if the cal- cium hydrogen carbonate concentration be- comes too low. Because of the sensitivity of the marine water inhabitants you must by all means avoid this. Regular addition of sera marin COMPONENT 1 Calcium and sera marin COMPONENT 2 Calcium pH-Buffer allows maintaining an even concentration in an uncomplicated way. The two component buffer system requires two bottles. Both components are present in high concentrations, which would not last when combined. The calcium level in nature is approx. 450 mg/l (ppm), the carbonate hard- ness is approx. 9°dKH. It is advisable to raise the carbonate hardness to 10°dKH in an aquarium. You can reliably monitor the calcium level and the carbonate hardness with the sera Ca-Test and the sera kH-Test, respec- tively. Why do these levels sink? Corals and mol- lusks, in particular, precipitate calcium hydro- gen carbonate as calcium carbonate by means of their endosymbiontic algae, using it as construction material of coral skeletons and mollusk shells! A growing coral thus withdraws a part of the buffer system from the water. Some mollusks are also able to do so. For ex- ample, giant clam species (Tridacnidae), which become more and more popular, withdraw calcium hydrogen carbonate from the water for their shell growth! Bacteria living in the bot- tom gravel can also cause local precipitations due to their metabolic products.