Zhongke is...? Specialized in design and construction of re-circulated freshwater and saltwater fish farms. ? Specialized in upgrading and improving older or disfunction systems. ? Specialized in aquarium like ocean pavilion. ? Has upgraded many farms; with drum filters or disc filters, oxygen systems and ultra violet. These farms are making after this upgrading at least the calculated production. ? Is supplier of design and materials for farmers who will do the upgrading of installations themselves.