I doubt there is any issue with brood production and dosing. CO2/Excel are more likely issues here. Those did influence brood production in RCS and in CRS. Quite a bit. I have a non CO2 tank that is dosed fairly regularly due to emergent growth. Production is at least 3-5X higher, whereas the dosing of ferts is independent and the same between tanks. They still bred in CO2 enriched tanks, just nowhere as much.
If you have non CO2 tanks without emergent growth, then there's not a great need for dosing to begin with.
So............moss tanks without CO2, soft water, decent TDS etc......not bad places to grow them.
High light tanks, CO2 jacked up, ferts are likely the least of your issues.
How many folks kill fish with ferts?
How many kill fish with CO2?
Think the scenario is any different for shrimp?