Quote " -there is an antibacterial action too."
It is not antibacterial and neither do Thetford claim it to be.
Quote " Sorry Damian but experience tells me the “pink” addition works,"
Dusty, I have no reason to doubt you, but my experience of dealing with several hundred issues of blocked flush pipes and pumps, all had the same common denominator.Thetford Pink additive.
I can only assume that Elsan has a different recipe for their offering, which may or may not be the answer.
Having said that , the algae problem does not seem to affect every system the same.
As far as it goes, it is personal choice so if folk want to use it, go ahead and I will be happy to keep on fixing the problems as they arise.