The study compares two different graphic marking systems designed to help L2 learners of Swedish notice and realize phonological length. In System A, 22 L2 learners read aloud three /VːC/ words with length marked under long vowels and three /VCː/words with dots under short vowels. Twenty-two other L2 learners read the same words marked by the other system (System B) that underlines long vowels and long consonants. As a control group, 20 native Swedish speakers read the same words without any marking. We measured and compared the temporal realizations of the six words by all the three groups. System B readers realized Swedish phonological length more closely to the way that native speakers did, compared to System A readers. These results suggest that prompting both long vowels and long consonants can be more effective than marking long and short vowels.