FYI, smaller tanks need topped off for evaporation, CO2 changes are much larger and big issues for smaller tanks.
Ferts: just make a DIY liquid and dose richer.
You have a lot of light and a small tank.....CO2 demand is going to be quite high, adjust the light up to reduce intensity.
CRS adults are somewhat tolerant of CO2, but not the breeding and fry.
You will always get better growth, breeding/brood production with non CO2 methods and shrimp.
I would suggest a better valve than the fabco, you spent a wad on the tank, the light and the soil, even the hardscape, but the single MOST LETHAL thing........you went cheaper on????
You cannot kill shrimp with light or ferts(unless you really go nuts).
CO2? People do it every week on forums and kill fish which are even tougher.
Less light= less CO2 demand.
I have 1.2 W/gal of T5 lighting on this 350 Gal tank and the Gloss grows nice and tight: