I use a natural method to spawn-using either 5-10gal soil based-full to the top with water, lots and lots of stem and floating plants, no filtration other than what the plant provide. I add a oak leaf to float to use to anchor the nest-he will either use that or water lettuce.
Along with the breeders-the tank will also have lots of trumpet snail, ramshorn and pond snails-they help maintain the system as well as produce microorganisms for fry food. I also keep lots of red cherry shrimp in the spawning tank to complete the little ecosystem.
This is what my 10gal spawning tanks look like
This is my 5gal I use to spawn