Just about to build a bund for a 50 m3 liquid fert tank. What is a sensible height to build the bund wall? Was thinking about 1.2m high. Have seen some at almost 50cm but that would mean a 16x8m pad which is bigger than I want to build. How do people mange the hoses with a higher wall? Does anyone put a pipe through the wall with a fixing on the other side to avoid having to clamber over all the time?