I am going to be moving soon, and need to make some changes to my tank. I was thinking about getting new substrate. What do you guys suggest for black? I was thinking about Flourite Black sand, but open to suggestions. The tank is 180 gallon, 72x24. Right now I have activ flora, but the depth is lacking in several areas, my guess I need 5 bags to get to correct depth, and it difficult to find anymore.