I am not going to say they will last, but you never know. I have seen some Armatus that had to have been 24" and still together in a tank that didn't look much bigger than mine. I will be adding an aro when I can find one at the right price and in the right condition.
I use to have an aro in with them when they were in the other 8ft that busted a seam. The big Arm would charge at him from time to time and the aro would mess with the Arm every now and then but that seemed to be it. I love that combo, so gl to ya.
Play sand can be a pain to vac. You just have to be a little more careful. I am not too worried if I loose some either. It is so cheap. I will have to get a pic of it when I get the black back ground on and turn the actual canopy lights on. It looks better than just about any sand I have seen or owned. If I position the powerhead down a couple degrees more it will give that awesome ripple affect on the bottom. They key is not to get it blowing the sand around to hard as to make a hole or get particles floating around. The stuff is pretty solid and packed down too.
It's been about 3 days so in about 3 1/2 weeks I will know hopefully how things will work out. Always subject to change. Thats another reason why I stuck that filter on front temporarily, just to keep the bio media going. That way I can have my 75G emergency tank ready if I need to remove one. How I will catch them is another story lol