Hello all, I am sorry for this, but I need to retract my request for help. I am not sure LimmaGUI can cope with replicates in the same block (as this gal file shows). I was not expecting them to be in the same block and am getting the files checked. Sorry to have wasted anyone's time, but I might be back once this problem is sorted out... Thank you and my apologies again, Liz Brooke-Powell [[alternative HTML version deleted]]