diff --git a/src/survivor_selection/survivor_selection_methods.py b/src/survivor_selection/survivor_selection_methods.py
index 4848c98..80c396d 100644
--- a/src/survivor_selection/survivor_selection_methods.py
+++ b/src/survivor_selection/survivor_selection_methods.py
@@ -17,7 +17,7 @@ class Survivor_Selection:
     def fill_in_best(ga):
         """Fills in the next population with the best chromosomes from the last population"""
 
-        needed_amount = len(ga.population) - ga.population.total_children
+        needed_amount = len(ga.population) - len(ga.population.next_population)
         return ga.population[:needed_amount]
 
 
@@ -25,16 +25,23 @@ class Survivor_Selection:
     def fill_in_random(ga):
         """Fills in the next population with random chromosomes from the last population"""
 
-        needed_amount = len(ga.population) - ga.population.total_children
-        return random.choices(ga.population, k=needed_amount)
+        needed_amount = len(ga.population) - len(ga.population.next_population)
+        return random.sample(ga.population, needed_amount)
 
 
     @append_to_next_population
     def fill_in_parents_then_random(ga):
         """Fills in the next population with all parents followed by random chromosomes from the last population"""
 
-        needed_amount = len(ga.population) - ga.population.total_children
-        parent_amount = min(ga.population.total_parents, needed_amount)
+        needed_amount = len(ga.population) - len(ga.population.next_population)
+        parent_amount = min(len(ga.population.mating_pool), needed_amount)
         random_amount = needed_amount - parent_amount
 
-        return ga.population.get_mating_pool()[:parent_amount] + random.choices(ga.population, k=random_amount)
+        # Only parents are used.
+        if random_amount == 0:
+            return ga.population.mating_pool[:parent_amount]
+
+        # Parents need to be removed from the random sample to avoid dupes.
+        else:
+            return ga.population.mating_pool +\
+                   random.sample(set(ga.population)-set(ga.population.mating_pool), random_amount)