A pattern appears in smoke renders: How to fix?

[4dartist]

Here's a render of what we have so far, i just threw in a 'solid' from aftereffects as a background.

http://www.4dartist.com/cgtalk/smoke2.mov

Made some progress, we are pretty close, just need to get it to stick to the ground more, but still grow up. Thanks for your help.

PS still have no idea where the manuals are..