Clean power?
I don't know what your definition of "clean power is" but what I can tell you is that 220V is nothing else but 2x110V phase = 220V.
There's absolutely nothing more or less clean about 220V vs 110V unless you are talking solar power or something...
In a normal household environment, quite a few of the devices you use in your 110 volt circuits create electromagnetic fields in the wiring that can have health consequences and make people ill. That's where I first came across the term "Dirty Power". Not only can these cause health issues, but they can have an effect on high output devices, such as ballasts.
By cleaning up these EMF's with devices such as Stetzerizer filters, you can clean up the quality of power delivered throughout your system.
By running your ballasts on separate 220 volt circuits, you avoid alot of dirty power problems that plague 110 volt circuits running in the house caused by appliances, and you dont have to lay out the money for the Stetzerizer filters.
I've heard claims that the Stetzerizer filters will save money on electricity in houses that are running 1kw ballasts on 110 volt circuits with alot of appliances.
http://www.amazon.com/gp/product/B0...mp=1789&creative=9325&creativeASIN=B00488K5NW
http://www.blockemf.com/catalog/article_info.php?articles_id=26