De-fragmentation of a SSD is useless by design. Fragmentation is only an issue of HDDs where the reading/writing head has to move all over the disks in order to "collect" the different parts that together build your data (e.g. the audio files of an album). De-fragmentation does the following: It "collects" the different parts of your data and rearranges them so they are stored subsequently on the disks meaning the head does not have to move that much in order to read out the data which leads to faster reading speeds.
For an SSD on the other hand fragmentation is not an issue. It reads fragmented data just as fast as not fragmented data. So besides reducing the SSD's lifetime de-fragmentation would also be completely useless.
SSD's have another issue though. They can write onto the entire storage but they can only delete entire blocks (can't remember the exact details right now but you can google it, just look up trim on Wikipedia). That's what trim is for. So what happens is with time there are a lot of incomplete blocks on your SSD, partially filled with valid data, partially filled with data marked for deletion. But that data cannot be physically deleted because the blocks still contain valid data. Now trim comes into play and rearranges the data so all the valid data is stored in a way it fills up as much entire blocks as possible, leading to the "marked for deletion" data also filling up entire blocks. And now those entire blocks can finally be physically deleted making room for new data.
In short words: De-fragmentation of SSDs does nothing useful but (in theory) destroys your drive.