Hi Tony,
Is the soil/mud you are using is Fertile one??
If not mix 'Rock Phosphate' (40 g) and Mineral Mixture(1 packet) to it.
Use cow/Buffalo dung which is 3-5 days old.(Not the fresh one)
Depth Should be 4-5 Inches only
Please note the re-growth/expansion of Azolla depends on the soil...