Remove the bio-balls and replace them with Live Rock rubble, or better yet LR rubble and chaeto. You would have to scrape the paint off the back of the tank and add a light. There are lots of threads about doing this. The reason for removing the bio-balls is they collect a bunch of crud, are hard to clean and dont allow for a complete nitrate cycle. The way I understand it (I not saying its right) is the bacteria that convert ammonia to nitrite to nitrate can live on the surface areas of things (rock or bio-balls) but the bacteria that get rid of the nitrate need lower oxygen areas such as the inside of rock which isnt available in a bio-ball. Turning the 2nd chamber into a fuge by adding chaeto will improve filtration and help remove nitrates. Maybe someone from the chemisty forum will chime in too.
PS Aquascaping is VERY cool.
