I have the below set up, run my Penguin without bio-wheels, but with filter media. I change the media about every 3 weeks. I currently do 10 gal. water changes every 10 days. My Nitrates are almost always around 60. Never thought too much of it, but my Coral Beauty died yesterday out of the blue, no signs of sickness. Ammonia, PH, SG, temp, Nitrites are all OK. I've reduced my feeding recently from twice a day to once a day in hopes of lowering the Nitrates, but it seems to have no effect. My bio-load may be a bit high, and was wondering if a skimmer would be helpful.