Newbie with Algae Bloom and some equipment questions

[Biergott]

Hello,

I just returned from a business trip and my wife's friends were taking "care" of my aquarium while we were gone.

Anyway, the fish were obviously overfed (by the looks of the greasy fingerprints all over the lid, their kids got to feed the fish), and the light was never turned off.

Obviously I need to do a major water change and clean all of the decorations.

I have a 36 gallon, bowfront, with tropical community fish and have never had any issues. I have an Emporer 280 Bio-Wheel and run API Ammo Carb in the extra media slot.

In the past 4 weeks leading up to my trip, I noticed that the water has been becoming more cludy, more quickly though.

The water has always been crystal clear, and normally, I would only have to do 25% water changes every 2-3 weeks (I use an Eheim Gravel Vacuum every week)

So, my questions are:
-Would adding an additional Emporer 280 filter help with water clarity?
-Can I "over filter" my tank? So, would it be bad?
-How much water can I safely change to get rid of the Algae?

Thanks so much! This seems to be a great forum!

Jeremy