If your solution is *TO* basic then add more GBL, if it's to acidic then add more NaOH (solution) .. if you read up and take your time then you will have a decent end product - take yer time with it!
Also make sure you use GLASS and not METAL for all yer rxn's ..
GBL is getting a bit hard to come by, and it is a listed precursor in the US - you can be charged with intent to manufacture if you get caught ordering GBL and have so much as a recipe for GHB bookmarked - people have gone down for less...
Given that it's a listed precursor, I would be weary of any source within the US who is offering it at a to-good-to-be-true price.. (read: expect to pay a lot if yer in the states) ..
Sources state that you can get small amounts from anyone who is in the business of making electronic circuit boards .. look around..
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"I am not one of those weak-spirited, sappy Americans who want to be liked by all the people around them. I don't care if people hate my guts; I assume most of them do. The important question is: 'What are they in a position to do about it?'"