Thanks for your input Paul.
Some sort of netting device would be ideal, though I don't know that the overflow would be the best area. There is a lot of detritus being pulled from the tank as I am sure you could imagine, and this would mean nets full of sludge. Though the outcome of picking eggs out of the nets would be worth it, I don't know if it is something that could be conducted on a routine basis. Also, most of the eggs released in the water column are consumed within minutes of birth. Of the
demersal spawners in the tank, I have witnessed spawning of both the P. Hepatus and N. Vlamingii. I can say that the coloration of P. Hepatus is quite stunning during courtship rituals!