25-05-2015 Composting Heater in the making. I first used some old building rubble to make a Base to allow some aeration from the bottom. Then made a 200mm (8") layer of Horse manure and Straw. Next I coiled some Low pressure Irrigation pipe, 15mm, from the centre outwards, about 200mm apart. Placed bricks upright on top to hold the pipes in place, then topped it with another layer of Horse compost. Continued until the final spiral of the 100m pipes ended at the edge and covered with a last 200mm layer. I linked the pipework into my current setup do that water is pushed from the Sumps through the Heater pipe and returns to the top of my FT. Within an hour the water temperature rose from about 13deg C to around 20deg C…. Not bad I think