I frequent the fishkeepingforum as many of you may know, Jimthefish on there recomended a sub of John Innis No2 and kids play sand and a mix of 3 to 5 mm grit and play sand on top to stop the John Innes from floating in the water. I've used this method 3 times it it has to be said that I am getting better results from this substrate than I have with the tetra substrate I bought last year for a small set up I have. I'm growing a number of different crpts in these tanks and I'm shocked at the difference between the two substrates. Does anyone else use a similar sub? The only problem I get is the fact that the sand compacts easily. To irradicate this I bought a load of Malaysian funnel snails to borrow in it. They seem to be doing the job.