The breeder (I won't mention names) who told you that is an idiot. No way does a 4 foot tub house an adult male burm. My male is 5 and 13 - 14 feet long. How would I cram him in there?
And I have been using melamine for almost 20 years. Always made my own cages (even for bps). It might need replacing every 8 - 10 years, but for the price, it's still more cost effective than buying something premade. Besides, I have NOT found a commercially made enclosure that will house adequately (IMO) any snake larger than 10 feet.
Chris