diff --git a/R/chart_Series.R b/R/chart_Series.R
index e4afd14c..0a603035 100644
--- a/R/chart_Series.R
+++ b/R/chart_Series.R
@@ -522,10 +522,8 @@ add_TA <- function(x, order=NULL, on=NA, legend="auto",
 
     plot_object$add_frame(ylim=range(na.omit(xdata)),asp=1)  # need to have a value set for ylim
     plot_object$next_frame()
-  # add grid lines, using custom function for MACD gridlines
-  lenv$grid_lines <- function(xdata,xsubset) { 
-    pretty(xdata[xsubset])
-  }
+  # add grid lines, using y_grid_lines function from replot_xts object
+  lenv$grid_lines <- plot_object$Env$y_grid_lines
   exp <- c(expression(segments(1,grid_lines(xdata,xsubset),NROW(xdata[xsubset]),grid_lines(xdata,xsubset),
                                col=theme$grid)), exp,  # NOTE 'exp' was defined earlier to be plot_macd
   # add axis labels/boxes