How are you going about conditioning them?
Here is what I am doing currently. I have a mentor on another site and this is what he does.
"You condition them prior to introductions. Feed them high protein 2x/day. Brine shrimp and beef heart work well. I used to use chicken liver as well. You need to change the water after every feeding of beef heart or livers. After a week, put the male in the spawning tank, continue feeding until they eat not more. Once you have a nest, time for the introductions. You can condition the male in the spawning tank, but you have to clean ALL uneaten food 15 min after feeding. All this is subject to change, you always lead from the male, when he is ready, it's time. The longer the female has the high protein diet, the larger the spawn."
Once the two are introduced to the tank (her in the the chimney, him outside with a nest already blown), she will produce eggs more readily. Also, a change in the type of water is supposed to help the spawning process. I'm going to gather fresh rain water for the spawn tank.