If you place marbles and small rocks in the dish it gives them something to push against and it helps them to turn over. Every one of my water dishes has those in it just for that reason. I am so sorry to hear about your baby.
That is heartbreaking -- so sorry for your loss. Guess I will go home and be sure to put some pebbles in CherryBomb's dish -- I couldn't bear it, my heart goes out to you.
While it is normal to beat yourself up over this, even if you had been at home it still could have happened. I know words are hollow, but it does you no good to blame your self. I lost a box turtle a couple of years back to over heating and it was just a 2 minute window when I last checked on it.