I am looking for recommendations on what substrate to use for my new tank. I am having a custom acrylic 240 gallon (96Lx24Wx24H) made and will be housing a single 12" or 18" Piraya Piranha. I am thinking of using some kind of thick black sand or fine black gravel. I don't like the look of large pebbles, so that's why I say a finer gravel. It's not going to be a planted take or anything. Not yet at least. I would want something that is relatively easy to clean with a python. And hopefully doesn't require any extra work like having to wash it. Unless all substrates are better when washed (I'm not sure). Does anyone have any links or recommendations for black sand or gravel? I'm hoping I can order it online if possible or easily pick a few bags of it up somewhere.