I have a new 20 litre tank (roughly 5 gallons) that i set up last night and have started cycling. I want a natural sand colour, how many Kilograms of sand would i need for this tank? I've heard pool filter sand is cheap but when I looked it is only sold in large quantities. I will be planting the tank so id probably need about 2 inches of sand. Also if you know anywhere in the UK where I can get natural coloured sand for a decent price I would appreciate it. I don't want to spend a lot of money on it, Preferably £10 or less. Thanks!