I hope this helps somehow.
I have CRS SS, CBS SSS, OEBTs and blue velvets (and crs/cbs babies) in this tank:
I dose 1/6 of PPSpro daily and I have co2 24/7 at 1bps.
I don't use alkaline buffers.
PH is constant 5.5 day and night.
KH is constantly less than 1
GH is 6, with seachem equilibrium and mosura mineral plus.
NO3 is less than 5
PO4 is less than .5
Temp is 70F
TDS is 150
How is ph constant? Well this is what i think does the trick:
Big Under-gravel filter and ~5" akadama drl substrate and co2 24/7.
Lots of filtration and water flow and lots of surface agitation WITHOUT splashing.
I change water when I clean my canisters only which is every 4-6 months. I only top off with DI water (0 TDS).
For what I understand ph swings are not a big concern for adult shrimp but it is for shrimplets. That said, the most successful shrimp keepers/breeders I know that use co2, use it 24/7.
Edit: I just want to add that this tank is so easy to maintain that is actually boring. WC 2-3 times a year, trimming every 2 months, feeding every other day...zzZZZzz