The problem I am having at the moment is a very bad case of algae. The algae is dark green and slimy. It is covering all the plants and gravel in the tank. It is easy to remove by hand, but grows back very quickly. I also notice that the tank has a swamp smell about it. I have been using a product called Protalon-707, this has helped a little but the problem still remains. The tank has been running close to a year, I originally started with two tubes over the tank, I have now increased this to four. The tank is home to eight discus and four bristlenose, the bristlenoses will not eat this algae. I was doing 50% water changes twice a week, but I have not done any water changes for the last week since I have been using Protalon. The tanks lights are on ten hours a day, after testing the water tonight I have found that my Nitrate is 160, and the Phosphate is 5.0. I have also tested my tap water, and the Nitrate is 5.0 and the Phosphate is still 5.0. If I remove the algae from the plants, the plants will pearl like mad, this will only last a few days and the green slimy algae returns. Does anyone have any suggestions on how to kill this algae as I am on my wits end?