If your shrimp aren't coming from tanks that are dosed regularly with fertilizer, you could run into problems. That'll be more of an issue to deal with than pH.
What's your GH? KH? Those are important parameters to know.
Unless you're an experienced shrimper, it may be better for you to keep Neos until you get the hang of what works with even lower grade Crystals.
If you're absolutely set on Crystals, then you're going to need to do things slowly. Stop CO2 injection, stop the fert dosing and allow the shrimp to settle for a few days before you start things up again. And then, do so slowly and incrementally.