Good afternoon @coenecorys and welcome to the ODK community forum !
When you get a chance please take some time to Introduce yourself here! - #1211 by bcheye It helps to build the community 
So you get a csv from Aggregate's database and then upload this csv file to your own PostgreSQL database ?
Could it by a matter of decimal value separator (./,) or quoted numeric strings "3.869542"...
What tool do you use to pull csv to your database.