Anyone running biopellets on approx 700G system?

[Jaws]

Thanks but I'm moreso interested in how many mL people use and how long it takes before replacing them so I can budget for "X" number of dollars each month. That way by the time I need to replace lets say 750mL of biopellets, I'll already have a fund set aside to purchase them so I'm more prepared for the ongoing monthly costs that come with a large reef tank.