Quick picture of the chamber 1 basket/director.
Works like a charm. All 3 chambers have consistent water levels and the water is flowing perfectly through the media. Really happy with how it's turned out.
Top shelf is foam, cut from the stock block that is supposed to go in chamber 2, cut it to about an inch thick. I've made 2 so it makes maintenance easy. There will be a thin floss pad sat at the bottom of chamber 1 and 2 to trap any detritus that manages to bypass the foam so again weekly cleaning is easier.