i use pknuke in the water to kill any unwanted growth..
Sounds a lot like you need to flush it all out replace tubing then either have a kill coil or pknuke the water.
not sure why the liquidutopia isnt working for you though..
I use 2 drops of pk nuke per 1L of de-ionised water (destilled is fine, but de-ionised is just slightly purer)
edit
having looked at the pics.
im going to wager that you didnt flush out the rads before installing them.
and they were either contaminated during manufacture (usually the case) or they have had dye in them at some point..