diff --git a/src/ZSOLVER/tensorproductmultigrid_Source/discretisation.f90 b/src/ZSOLVER/tensorproductmultigrid_Source/discretisation.f90
index 92c5800f22fb433ce66986779960bf5335b2624d..e45406f0d75a57fb559a342a5e47f04a9a50300c 100644
--- a/src/ZSOLVER/tensorproductmultigrid_Source/discretisation.f90
+++ b/src/ZSOLVER/tensorproductmultigrid_Source/discretisation.f90
@@ -148,7 +148,7 @@ private
 
   real(kind=rl), pointer , contiguous , dimension(:) :: zt1d_discretisation
   INTEGER                                            :: zt1d_discretisation_size = 10000000
-  INTEGER , parameter                                :: zt1d_discretisation_size_factor = 4 * 4
+  INTEGER , parameter                                :: zt1d_discretisation_size_factor = 4 * 8
   INTEGER                                            :: nt1d_discretisation_top = 0 , nt1d_discretisation_max = 0
   
   INTEGER , ALLOCATABLE, DIMENSION (:)               :: nt1d_discretisation_pointer , nt1d_discretisation_pointer_ksize