Planted Tank Guru
Join Date: Jul 2010
Location: British Columbia, Canada
I've used a UV sterilizer 24/7 in my planted discus tank for a couple of years now.
Besides dealing with a number of potentially harmful pathogens within a tank, it has many other benefits imo.
It improves/provides water surface agitation maintaining a film-free environment (e.g. discus' shedded slime coatings); assists with good water circulation within the tank; oxygenates; and most of all, helps a great deal in maintaining crystal water clarity at all times.
It's also great when used in conjunction with a properly positioned circulation pump, power head, spray bar, etc., which prevents or deters unwanted algae, e.g., hair/filament, or dust, algae, from attaching to the tank's glass walls, thus keeping it in the water column where the UV can pick it up & destroy it.
I wouldn't be without one.