Question about undergravel filter conversion

For some reason about 50 days ago I started to get an outbreak of
either algae or waste in my tank. It gets pretty bad....on the glass,
decoration and causes me to do my tank cleaning and water changes much
quicker than I did prior. Within a few months of this starting, I:

* Added ceramics to my filter for bacteria harvesting

* My algae eater died after 4 years of good service

* Instead of using the porous sponge-like media for my large waste
catcher in the filter, I began to use the finer wool-like material
instead.


I did get a new algae eater but he died within 3 weeks. The brown
contamination began short after his arrival. No other fish have expired
and they have all been in this tank for at least 18 months (some have
been for YEARS). (This is a freshwater tank, FYI)

So yesterday it was suggested to me to go back to my original
filtration media (the sponge-like block, plus my usual carbon and
ceramics) but ADD under gravel filtration.

As far as I know I've set it up correctly. I've got the plate under my
gravel, the 1" tube coming up with the power head pulling the water
from it. The power head is shooting the water back towards the other
side of the tank where my hanging power filter will catch the debris.

Right now all of my decorations have been soaking in a diluted bleach
solution which seems to have really cleaned them up. I know now I need
to rinse them and let them sit in a de-chlorinator solution for another
day.

My questions: Have I set up the UGF properly? Will this help the
problem I'm describing? I cannot myself determine if this "brown muck"
was algae or waste. Also, would you suggest a hanging cannister filter
rather than an over the back power filter?

One thing that was pointed out to me was that I got in the habit of
leaving the light on 24/7...which i guess helps algae growth? I'm sure
to leave it off during the day now.

Any suggestions or tips are greatly appreciated! I've run this tank
since 2000 and never had any problems and now this. I just am not sure
what caused this change although I'm guessing between the media change
and maybe my AE dying, it could be a combination...?

Thanks all.

Below are the products I'm using:
Filter:
http://www.petsmart.com/global/produ...138288092 425

UGF:
http://www.petsmart.com/global/produ...138288124 689

Power head:
http://www.petsmart.com/global/produ... ua+clear&N=2