diff --git a/base2k/src/znx_base.rs b/base2k/src/znx_base.rs
index a168e18..c8636f3 100644
--- a/base2k/src/znx_base.rs
+++ b/base2k/src/znx_base.rs
@@ -113,7 +113,7 @@ where
 
     fn zero_at(&mut self, i: usize, j: usize) {
         unsafe {
-            std::ptr::write_bytes(self.at_mut_ptr(i, j), 0, self.sl());
+            std::ptr::write_bytes(self.at_mut_ptr(i, j), 0, self.n());
         }
     }
 }