just start over. You could be chasing that leak for quite a while. Not sure what the "blue glue" is, but I have never had a problem just using the standard pvc
primer (I like the clear) and glue. Since this is on the return line, there will be a little pressure if you are using a valve to throttle the flow so you want a good seal.
You will find plenty of debate on what glue is "safe" for your tank. To date I have not had a single issue with using the above mentioned method. If you are in fear of the smell and getting chemicals into your system, just let it set a day or two.