diff --git a/day09.py b/day09.py
index 66517d6..d9a66e4 100644
--- a/day09.py
+++ b/day09.py
@@ -15,17 +15,9 @@ def getCaveMapFromInput(puzzle_input: List[str]) -> Grid:
 
 def getLowPoints(caveMap: Grid) -> List[Coordinate]:
     lowPoints = []
-    for x in range(caveMap.minX, caveMap.maxX + 1):
-        for y in range(caveMap.minY, caveMap.maxY + 1):
-            thisPoint = Coordinate(x, y)
-            lowest = True
-
-            for t in thisPoint.getNeighbours(includeDiagonal=False):
-                if caveMap.get(t) <= caveMap.get(Coordinate(x, y)):
-                    lowest = False
-
-            if lowest:
-                lowPoints.append(thisPoint)
+    for point in caveMap.getActiveCells():
+        if not sum((caveMap.get(t) <= caveMap.get(point)) for t in point.getNeighbours(includeDiagonal=False)):
+            lowPoints.append(point)
 
     return lowPoints
 
@@ -35,7 +27,7 @@ def getBasin(caveMap: Grid, start: Coordinate, visited: set) -> set:
         if n in visited:
             continue
 
-        if caveMap.get(n) != 9 and caveMap.get(n) != 99:
+        if caveMap.get(n) < 9:
             visited.add(n)
             visited = set.union(visited, getBasin(caveMap, n, visited))