Hey i was wondering what the formula is for how much air is used by the cylinders every time they go in or out?

I’m assuming that you want to calculate the pressure drop in your air storage.

Because you have a different pressure and volume in your storage tank from your actuator, you need to calculate the mass of air used.

You need to calculate the mass of air it takes to fill the volume of the cylinder (and all the tubing) using the ideal gas law (PV=nRT or PV=mRT/M more commonly) for the set pressure, then subtract it from the mass of air in your storage tanks (as calculated with the idea gas law). Then calculate the new storage pressure based on the amount of mass left in your storage tanks (again with the ideal gas law).

There should be examples on how to properly apply the ideal gas law in a High School level Chemistry book.