Very interesting topic, the club i fish insist on carp care solution and seem to favour propolis as the one to use, having read comments about maybe sealing in nasties i am not keen to use it, i bought the propolis to replace my ancient bottle of Klin-ik, that is maybe 15 years old, i was gonna bin the Klin ik but maybe i will keep it for a while...........though 15 years might be pushing it a bit