Brown residue on inside of tank

Question
QUESTION: Hello Karen,
         I've had an aquarium for about a year with no problems. I recently gave it up to a friend and she decide to buy a new tank (the tank contains 7 x-ray tetras, 2 tiger angelfish, 2 peppered corys and a bristlenose catfish). We gave the tank the nessecary time to settle and added the fish. two months has gone by and a brown residue has appeared covering most of the glass, ornaments, pump & filter. Also the Catfish has died a sudden death and almost completly disintagrated, ever though being alive a few days before.
ANSWER: Dear David,
Sounds like your aquarium has Brown algae. Also known as 'diatoms' sometimes. This can appear in a newly setup tank or one that has a buildup of organics like nitrates. The good thing is it is generally easy to remove by using an algae scrubber or paper towel. Try increasing your water change schedule, and vacuum up as much of the algae as possible. You could also try adding some hardy and fast growing plants that can take up the nutrients that otherwise would feed the algae. Try putting extra carbon in your filter that could also help take up the extra pollutants in your water.

There are also algae eating fish that can sometimes remove a lot of the brown algae. Coincidentally, Bristlenose plecos commonly eat this algae. I'm sorry to hear yours died. These are my favorites. And usually they are quite hardy. Maybe there was something defective with that fish or perhaps a poor water quality problem. Maybe he wasn't getting enough to eat. The best foods to feed Bristlenose plecos is high-quality algae wafers, romain lettuce, spinach, or zuchinni. Remember plecos should be fed at night.

I'm sorry to hear of all your tank's trouble! Feel free to write with anymore concerns and best of luck!
Karen~

---------- FOLLOW-UP ----------

QUESTION: How do i add carbon to the filter?

Answer
Hi David!
What kind of filter do you have? Hang on the back power filters have cartridges that can have a small slit at the top where you can add additional carbon inside. To avoid destroying your bacteria on the filter and since you'll need to rinse the newly added carbon to get rid of carbon dust, just take a pitcher or bucket or tank water and slosh it around to get rid of the dust. It's usually very easy to add carbon to most all filters.

As always, if you need anymore help, feel free to write!
Karen~