Betta eggs not hatching

[Fishkeeper1010]

Hi I have had about 4 breeding attempts now with this pair of bettas and every time they wrap and spawn very quickly but the eggs don’t hatch and get eaten. 

Is either of the parent infertile or is it a water issue? I have really soft water with pH of 6.5 and no kh with 50 ppm gh.

I really want their fry what do I do?

 

[Fish Folk]

Before launching into a lengthy reply, help me understand a few facts about your experience:

(1) Have you ever successfully bred and raised Betta splendens before?

(2) Do you regularly breed and raise aquarium fish?

(3) Are you familiar with the breeding process for Betta splendens?

(4) Do you understand the development process for the labyrinth organ in Anabantids?

(5) Do you keep, propagate, or hatch any live foods regularly?

If you answer "Yes" to all of the above, we can get into specifics fast. If not, there's just a little learning curve. 

Edited January 14 by Fish Folk

[Fishkeeper1010]

I have been keeping betta splendens for at least 6 years 

I used to breed guppies, platies and have experience in raising baby fish

Yes I am very familiar and have done a ton of research into betta breeding, watching a lot of different breeders do it.

If you mean maintaining the humidity, yes I do have an idea about it

I have a baby brine shrimp hatchery as well as a thriving daphnia culture. 
 

I have a spare 20 gallon tank that I intend to use as the grow out.