Do fiberglass pools come with a serial number? I developed 2 major cracks (1/4 inch wide) in my 13 year old pool. This is the second year in a row that I have 2 major cracks. Last year 2009 the company repaired it but now two more appeared in different locations, it appears to be structural. Now I am looking for a replacement under the 50 year warranty. The installer went out of business & the manufacture wants proof that it's their pool.