I don't think you have a high bioload at all - I'd reduce the volume of feedings or reduce the frequency of feedings.
Want to hear about phosphates from feedings? 120 gallon tank, no skimmer, 7" Naso tang and a pair of 4.5" blue throat triggers, plus about 7-8 little guys that stay out of the way. The big three are total pigs and will take down piece after piece of nori, as well as Formula One, Spirulina, frozen Rod's Foods, etc. Last week the female trigger jumped out of the tank. She was going for me as I was dipping the feeding glass into the tank.
\ I just purchased GFO and a reactor and the suggested pump for the reactor, a MaxiJet 1200, for under $110 from BRS. Maybe this is a good way to go?
My live rock has become a phosphate sink. I'm swapping out all live rock soon, it's all old rock and very overdue. When I swap, I'm hooking up the reactor. That's the plan, at least.