Love it! I'm really digging wabi kusa... I have a good container, and tesco cat litter (used with soil & grit mix for my bonsai) so may start one up in the next few days. There are a number of wetlands near my home so might try one with local wetland moss and plants. Throw in a bit of driftwood root from my local beach, and bingo, welsh Wabi Kusa!
One question, as I'm still in the planning stage for my first aquascape I don't have access to tank water. Will rain water be ok? I have a large water-butt in my garden so a constant source of rainwater.