Sacrificial anode specifications are optional

There's an offshore jacket platform, and the area of each section has been worked out. How to choose the specification of aluminum sacrificial anode? The quality? Electric current? Please refer to the Cathodic Protection Manual compiled by Mr. Hu Shixin! Specifications refer to GB as far as possible, easy to order. Mass size for easy installation and average current distribution. Occurrence current and life can be calculated according to the relevant scale or cathodic protection manual!