Liz,
I'm going to have to agree with your friend about the hardness. With high hardness the shell has a build up of minerals making it more difficult
to hatch out. What Willie is doing works out for him but your water and my water are different. My water runs around 70 to 120 ppm hardness,
last check on around 4 to 7kh and ph 8.9. I use straight tap on all tanks(50 plus). When there is a spawning I pull out the eggs after one hour, either
place the eggs in straight RO or straight dechlorine water. The eggs goes in a one gallon bottle of pitcher. The pitcher is place inside the aquarium.
One hour before hatching 72 hours eggs are move to straight tap, water from another pair or water from the original pair. After a couple more days fry are free swimming and I could pour the fry back to the original pair or to a foster pair and last option is to pan raise.
I don't know if this answers your questions but I got a little carried away.
Cliff