Um, am I the only one that thinks a Rena XP2 on a 150 gallon is WAY too small?
I would suggest TWO Rena XP4s if you insist on a Rena!
Even better, get Fluval FX5. $200 on ebay, many MFKers love them, myself included (I own a Rena XP3 as well, for the record).
AND STOP FEEDING IT PEOPLE FOOD! Good large fish food: Hikari Massivore, Large New Life Spectrum pellets, and Omega one.