Archer is right on. Get the refund. Stop playing around with a tank you are not comfortable with.
I had a 50 gal once. It cracked overnight. 50 gallons of water on the floor. Ruined the rug, and the floor underneath drained into the basement. Now, you have a (small) risk of mold down the road...
I like the API kit with four or five tests using vials. Not happy with Salifert ammonia kit. I find it really had to match the colors to the test container. Just my opinion.