I just made a separator out of one of those. I had 2 of them and the sticks got broke on one. I used plastic canvas on one of the other top pieces and cut the holes out to slip them over the posts. If you don't have another piece from another one then you can use the plastic canvas and make a box that will sit in the bottom. Another choice is to fill the net breeder with java moss. I did this with one of my latest spans from a large sword and 6 of the babies survived. I don't think she had more than 10 as the babies were very large.
Anacharis, olodea, water sprite or anyhting thich with leaves will help the babies survive in the net long enough to save them in the morning, or at least a few of them. I will get you a picture if I can get one to turn out well enough.
She is a very large sword, about 2 inches and she like it as much as any fish likes these things but she is ready to pop, again. Will be here 3rd batch in 8 weeks.