Took a break from the forum for a bit. This tube that your refering to I havn't really paid much attention to. I didn't really plan or want them to lay eggs, but nature does what nature wants I suppose. I do recall seeing something from time to time, but I'll have to pay more attention to give you a real answer on this.
The way I've remembered it is.... she starts to get fat, and then one morning I see her not so fat anymore. Then I have to move a rock to actually see the eggs, they lay them in a cave that is part of the rock their anemone is on.