An UV filter wont help against the type of algae you describe. It will only
help against free floating micro algae like the type that makes the water
green.. It wont stop attached organisms from spreading offspring to other
parts of the tank.
It could help increasing the health level of your fish if they are plagued
by micro organisms in the water like fungus and bacteria. For example fin
rot, wounds, white "cotton" dots etc. But this should not be a problem if
the tank is well cycled and doesn't have to many fish because the imune
system of warm water fish should be able to deal with that.
It doesn't sound like an UV filter is what you need. Maybe less fish per
volume and more water changes. That won't make the algae go away, but it
could make them grow slower.

- Jon Olav


"Tony" wrote in message
...
I've been contemplating adding a UV sterilizer to my 75 G. freshwater
tank.
The prices aren't that expensive if it would be a positive addition.

I'm primarily considering it for 2 reasons: overall improvement of fish
health and assistance in the fight against algae.

Can anyone comment on the value of the sterilizer for these two things?

I'm having a horrible problem with algae that looks like hair growing on
my
plants. I remove all the affected leaves and within a few days it is
back.
I don't think UV sterilization will help with this problem, but I'm hoping
it might help with the bright green string algae that has been showing up
on
the top of my tank and in the biowheel output.

Also, if it will raise the health level of my fish and/or give them a
longer
life, I'd think it might be worthwhile.

I primarily have freshwater angels and loaches in my tank. (Along with
plecos and a few other fish.)

Tony