ok a while back i knocked over my lava lamp and broke the bulb and replaced the bulb with another 40 watt. now the black lava seems sit at the bottom looking like a mountian. its connected to the coil. sometimes it does move but when it does it does in really big blobs and not small ones like my red one and eventually goes back to the bottom in a mound. is this a liquid problem? and if so how do i fix it.