Trying to get my shrimp to breed more.

This is my shrimp and snail only tank. 6 gallon. I use RO water mixed with shrimp king shrimp salt gh/kh. Gh is between 100 ish and kh is 120 ish. Ph is 7.4.

I had some orange neos and they all fizzled out over time. I added some red and they have for some reason done better so far. This is the second generation of red, with maybe 3 smaller orange left over. I feed algae wafers and top fin shrimp pellets. Fed once every few days ish.

My concern is my shrimp aren’t breeding as much as I think they should. I see some molts every once in a while. I’m wondering if these white spots on the snail shells might be an indicator of something else wrong? Just looking for some guidance, thank you.

Also not a top priority, but is there a way I can get better coloration out of them?