diff --git a/examples/features/o3_averaging/random_liquid_water/input.xml b/examples/features/o3_averaging/random_liquid_water/input.xml
index 4a782ce2a..e8b196b7e 100644
--- a/examples/features/o3_averaging/random_liquid_water/input.xml
+++ b/examples/features/o3_averaging/random_liquid_water/input.xml
@@ -16,7 +16,8 @@
       <ffsocket name='base-noo3' mode='unix' pbc='false'>
           <address>h2o-noo3</address>
       </ffsocket>
-      <random> True </random>      
+      <random> True </random>
+      <prng> 54321 </prng>
   </ffrotations>
   <system>
     <initialize nbeads='1'>
diff --git a/ipi/engine/forcefields.py b/ipi/engine/forcefields.py
index 3abaa2648..f74e06831 100644
--- a/ipi/engine/forcefields.py
+++ b/ipi/engine/forcefields.py
@@ -231,7 +231,10 @@ def _poll_loop(self):
         finished.
         """
 
-        info(f" @ForceField ({self.name}): Starting the polling thread main loop.", verbosity.low)
+        info(
+            f" @ForceField ({self.name}): Starting the polling thread main loop.",
+            verbosity.low,
+        )
         while self._doloop[0]:
             time.sleep(self.latency)
             if len(self.requests) > 0:
@@ -242,7 +245,7 @@ def release(self, request, lock=True):
 
         Args:
             request: The id of the job to release.
-            lock: whether we should apply a threadlock here 
+            lock: whether we should apply a threadlock here
         """
 
         """Frees up a request."""
@@ -429,7 +432,7 @@ def __init__(
         super().__init__(latency, offset, name, pars, dopbc, active, threaded)
 
         if pars is None:
-            pars = {} # defaults no pars
+            pars = {}  # defaults no pars
         self.pes = pes
         try:
             self.driver = __drivers__[self.pes](verbose=verbosity.high, **pars)
@@ -1170,7 +1173,7 @@ def __init__(
             pars=pars,
             dopbc=dopbc,
             active=active,
-            threaded=True, # hardcoded, otherwise won't work!
+            threaded=True,  # hardcoded, otherwise won't work!
         )
         if len(fflist) == 0:
             raise ValueError(
@@ -1467,30 +1470,40 @@ def __init__(
         dopbc=True,
         active=np.array([-1]),
         threaded=True,
-        ffsocket = None,
-        ffdirect = None,
+        prng=None,
+        ffsocket=None,
+        ffdirect=None,
         random=False,
         inversion=False,
         grid_order=1,
         grid_mode="lebedev",
     ):
-        super(FFRotations, self).__init__( # force threaded execution to handle sub-ffield
-            latency, offset, name, pars, dopbc, active, threaded=True  
+        super(
+            FFRotations, self
+        ).__init__(  # force threaded execution to handle sub-ffield
+            latency, offset, name, pars, dopbc, active, threaded=True
         )
 
-        # TODO: initialize and save (probably better to use different PRNG than the one from the simulation)
-        self.prng = Random()
+        if prng is None:
+            warning("No PRNG provided, will initialize one", verbosity.low)
+            self.prng = Random()
+        else:
+            self.prng = prng
         self.ffsocket = ffsocket
         self.ffdirect = ffdirect
         if ffsocket is None or self.ffsocket.name == "__DUMMY__":
             if ffdirect is None or self.ffdirect.name == "__DUMMY__":
-                raise ValueError("Must specify a non-default value for either `ffsocket` or `ffdirect` into `ffrotations`")
+                raise ValueError(
+                    "Must specify a non-default value for either `ffsocket` or `ffdirect` into `ffrotations`"
+                )
             else:
-                self.ff=self.ffdirect
+                self.ff = self.ffdirect
         elif ffdirect is None or self.ffdirect.name == "__DUMMY__":
             self.ff = self.ffsocket
         else:
-            raise ValueError("Cannot specify both `ffsocket` and `ffdirect` into `ffrotations`")
+            raise ValueError(
+                "Cannot specify both `ffsocket` and `ffdirect` into `ffrotations`"
+            )
 
         self.random = random
         self.inversion = inversion
@@ -1632,12 +1645,12 @@ def gather(self, r):
 
         for ff_r in r["ff_handles"]:
             self.ff.release(ff_r)
-        
+
     def poll(self):
         """Polls the forcefield object to check if it has finished."""
 
         with self._threadlock:
-            for r in self.requests:             
+            for r in self.requests:
                 if "ff_handles" in r and r["status"] != "Done" and self.check_finish(r):
                     r["t_finished"] = time.time()
                     self.gather(r)
diff --git a/ipi/inputs/forcefields.py b/ipi/inputs/forcefields.py
index f2b205b8a..a9a8956a7 100644
--- a/ipi/inputs/forcefields.py
+++ b/ipi/inputs/forcefields.py
@@ -28,6 +28,8 @@
 from ipi.inputs.initializer import *
 from ipi.utils.inputvalue import *
 from ipi.utils.messages import verbosity, warning
+from ipi.utils.prng import Random
+from ipi.inputs.prng import InputRandom
 
 __all__ = [
     "InputFFSocket",
@@ -980,6 +982,14 @@ class InputFFRotations(InputForceField):
         },
     )
 
+    fields["prng"] = (
+        InputRandom,
+        {
+            "help": InputRandom.default_help,
+            "default": input_default(factory=Random),
+        },
+    )
+
     fields["ffsocket"] = (
         InputFFSocket,
         {
@@ -1004,6 +1014,7 @@ def store(self, ff):
         self.grid_order.store(ff.grid_order)
         self.grid_mode.store(ff.grid_mode)
         self.random.store(ff.random)
+        self.prng.store(ff.prng)
         self.ffsocket.store(ff.ffsocket)
         self.ffdirect.store(ff.ffdirect)
 
@@ -1018,6 +1029,7 @@ def fetch(self):
             dopbc=self.pbc.fetch(),
             active=self.activelist.fetch(),
             threaded=self.threaded.fetch(),
+            prng=self.prng.fetch(),
             ffsocket=self.ffsocket.fetch(),
             ffdirect=self.ffdirect.fetch(),
             grid_order=self.grid_order.fetch(),