two toned grass
 

I recently moved into a home that had a marathon lawn for a few years. A few
months after I moved in, some patches of the lawn died due to sprinkler
malfunction.
I put some Scott seed on the lawn, and it has grown back.

Unfortunately, now 90% of my lawn is dark green marathon and the rest is 10%
lighter green Scott's. And Scott's grows quicker. Therefore, I have a dual
colored lawn, and some of it is longer than the other.

I'd like to get the 10% back to looking like the rest. Will it due so over
time, should I put some Marthon seed over the Scott's, or dig up the Scott's
and put some new seed?

Suggestions welcome.