Is my toddler getting too much Iron?

I was wondering if anyone knew a little about iron consumption, my 13 month old has really dark poo and pebbles the past 4 days, she is still pooping and it doesn't hurt her however I Read that Dark poo means too much iron so when I looked into how much she is actually consuming it seems to be a lot. Her cereal says 5 tbsp= 100% of daily intake which is what she eats, she drinks the up to 18 month formula which still has iron in it plus she loves whole wheat bread, pita, cheerios and chicken and fish which all have high levels of iron. Lately she has been eating more cereal than usual too. Has anyone ever had This problem? THanks!