Hi all. I'm currently leak testing my 110ltr tank, which I'm planning to set up as a tropical, planted tank. My current idea is to set it up as an Amazon/S American biotope with a larger shoal of small tetra (front-runner so far is Ember Tetras), and maybe an Apistogramma species, but right now, I'm looking at substrate, and I was wondering what people's opinions were on using aquatic compost, with a top layer of gravel? This is what I'm thinking of using, although I'm aware I can get it cheaper than this: I live in a software area, and while I'm waiting for my gH/kH (and, indeed, my Api Master) test kit, my water company's website indicates water hardness to be 17mg/l. PH, when I lived at home (about a mile away, and in the same area), was roughly 6.5-6.8. Would I need to add a phosphate test kit to my collection? That's another area which is new to me. Here's a pic of the tank .... looking a bit bare, I know (obviously things are going to be moved around, and/or upgraded over time) In the past, I've always used gravel, so any opinions/advice would be most welcome.