I would put the birdsnest no more than 6" down. They like alot of light and low flow. The slimer is going to be really tolerant of anything, keep him higher for better color, due to their growth pattern keep him toward the back, that's where I like to keep my stags. I've seen that valida do all sorts of things as far as growth patterns, but they really need alot of light to maintain good color. I wouldn't put the valida or the birds nest in anything less than 300 PAR.