› Forums › Aquaponics Forum › Aquaponics Discussions › Hardware chat › Help with BSA Tagged: BSA, surface area This topic contains 0 replies, has 1 voice, and was last updated by Denisechester 1 year, 10 months ago. Author Posts 12 October, 2017 at 4:46 PM #2918 DenisechesterMember Hello, Can anyone help me with how to calculate the biological surface area of my system please? I’m using clay pebbles in a trial system and maths isn’t one of my strengths. How do I calculate m2 of surface area in a grow bed that is L78 x H32 x W47 cm. Many thanks, Denise Author Posts You must be logged in to reply to this topic.