[capta]

I've found that a standard broom handle will do nicely to clean my a/c lines. I've tried pool chlorine tabs for pools in the sea strainer, but it wasn't terribly effective and probably not the best for the environment.
The only sure fire way to keep the circulation lines for refer and a/c systems is an ozone set up. Not too expensive and pretty easy to do, but it will necessitate some creative thinking.

 

[capta]

Once the hose is cleaned out, go by West marine and purchase a short length of copper grounding foil. Cut a triangular piece about an inch wide and two or three inches long and roll it tightly into a short tube around a bamboo skewer. Remove the skewer (of course), drop it into your hose and push it gently down to your strainer with a pre-measured length of dowel. As the foil dissolves it will prevent growth in your raw water line. Replace the foil every few months.

Considering that all a/c units today use aluminum coils do you think this might cause those coils some electrolysis problems?