After using the tank 3 times, I discovered the cracked issue when I took off the cover from the tank. From the information gathered from the INTERNET, this is common issue with Ninja tank coating gel.
From Techpb forum
http://www.techpb.com/forum/index.php?showtopic=216449
http://www.techpb.com/ipb314/index.php?showtopic=204019
Do this -->
http://www.mcarterbrown.com/forums/paintball-news/210891-new-warranty-ninja-paintball-gel-coating-crack.html