can you defrag an ssd and if so what software is safe?

Tapeworm is correct SSD do not need defrag. If you are using Win 7 or MAC OS 10.6 or higher then your OS supports TRIM. TRIM is sort of like defrag for SSD. If you ahve an older OS like XP you will need to get a third party TRIM tool. for more info on TRIM just google SSD TRIM.