I'm new to breeding too and am having the same problems you are so I couldn't give you a solution. How old are your fish? From what I've read from other people is that it is common for younger fish to have several failed spawns before they know what to do with them. My pair is on their third spawn and I don't expect the eggs to make it 24 hours before they become snacks. I guess this is why they say patience is the key to discus .When you put mesh over the eggs did you put it close enough so the pair could still fan the eggs? I wouldn't be too worried quite yet