Phophates and Nitrates

[ABreefkpr]

A friend of mine changed tanks a while back. He went from a 300 Gal to a 108. The problem now is nitrate levels. He always registered high phosphate levels in the old tank but now he's got high nitrates as well. He moved his sand, 100-150lbs live rock, fish and water into the 108 about 2 months ago and has had the nitrate problem ever since. The levels don't seem to be dropping. And no algae problem with the high phosphate levels. He had bio balls in the sump but took them out about a month ago. No change. I got some sand and water from him for one of my systems and I too have a nitrate problem. What could it be
Any ideas? Anyone

Keith