In veg it would be fine but I wouldn't spray anything on buds in flower. Damp buds mold easily. Seems like a waste of time because any co2 from the water would just disipate in seconds not leading to any meaningful increase in ambient co2. You would be better off just breathing on them. The co2 would last just about as long.
If you have good airflow you don't need to worry about co2 at all....