BTW, just to clarify: Bacquacil is a brand name for Biguanide.

As Evan says, it's the copper that turns blond hair green--not the chlorine.

If you really want a low chlorine system rather than a non-chlorine system, salt water chlorine generation is the way to go. It keeps SUCH a constant level of chlorine in the water that you don't need nearly as much. Plus it's great for keeping your pool clear if you go away.

Evan, correct me if I'm wrong, but bromine is really more appropriate for hot tubs, which don't see much UV and can have very intense bather loads--and frequently get emptied and refilled.

I have NO idea what biguanide is good for. It's only advantage over bromine that I'm aware of is it's easier to convert a biguanide pool to chlorine than a bromine pool.