[jsm11482]

it is a seperate unit - the water runs through it and a UV bulb purifies stuff:

http://www.drsfostersmith.com/produ...&Ntx=mode+matchallpartial&Np=1&pc=1&N=0&Nty=1

for more info.

 

[jsm11482]

80$ for up to 125gal tank doesnt seem too bad to me if it really works....