Thanks for all the comments guys. To answer the questions above. I do about 100-150 gallon water changes once a week- This is only 15-20%. So it's really not that much. Most people are doing over 50%. Sometimes I have done every other week, but I think the fish are much healthier and happier with once a week, plus the driftwood is still bleeding so it clears up the water. Remember even though the tank is large and the filtration is great I still have many large fish that produce alot of waste.
Regarding the wattage usage. The two pumps are very effecient. They are rated at 1.2amps. The lights are rarely on because my garage has small windows at the top and give sufficient light for the fish during the day. I have three 300watt heaters and only run them during the winter months. I live in So Cal so it really doesn't get that cold in the winter and my garage is insulated pretty well. I also get a little heat from both the pumps. Plus with such a large volume of water, once it gets up to temp., it retains it's heat much longer than a smaller tank. I unplug the heaters all summer long. All in all it's pretty effecient. I have three other tanks as well, a 20, 75, and 240 and my electric bill for two months is around 300bucks for everything. So 150 a month. I could run one pump and turn the other off to save some money and still be alright with 4000gph, but I'm a nut for filtration. The more the better. Plus I am going to add more fish and these suckers are still babies. hehe. I hope this answers your questions. Feel free to ask any more.