VERY likely you missed using an option in Macrium Reflect's cloning process.
To do the cloning operation, you run the software and select the Source and Destination storage units, then select which Partitions on the Source unit you want to clone to the Destination. By default, it probably makes the Partitions on the Destination unit the same size as the originals on the Source. That is not really what you want, because your Destination unit has much more space available. Look closely a the screen where all those choices are made, especially at the bottom centre. Make sure the Partition on the Destination unit that is to be used for the copy of your main Partition from the Source is highlighted. Then click on the "Cloned Partition Properties" link at the bottom. This will open a new screen where you can change those properties to make the cloned Partition on the Destination unit as large as you can, so that it uses up all the space available there. When you have all these settings the way you want them, you can allow the system to do the job.
So, if you understand how to use this tool, re-do your cloning operation so that the SSD has a much larger main Partition and uses all the space it can get.