has anyone used JBL Aquatrop J?

has anyone used JBL Aquatrop J?
is it anygood?
effects on discus?

i found this site
http://www.jbl.de/uk/aqua/uk_20050.html

but i just wanna know from people who have actually used it.
thanks
Eric

It is good but chinese black tea will do just as good a job for 99% less cost.