I have a gas fireplace. I have not purchased a large tank. I hooked a small grill size tank to my gas line. The fire lights and burns 5 sec good, then goes to a tiny flame. Tried adjust flame knob and everything. Is this too small of a tank? Does pressure has something to do with it? I have appox. 50 feet of line also. Line comes in house, goes up to attic, goes over, comes down to fireplace. Im just wondering if Im screwing something up before I go and buy a large tank and the problem is not the tank at all. Please help. Many thanks in advance.