Cant do better than $200 for the new one. The 75 gpd Ill give you for $100. btw, you cant compare the bulk reef supply units to either of these. They use inferior filters which is why they are so cheap and you need to replace them often because they are cheaply made. You know what the saying goes, you get what you pay for. any of the ones I have will last you way longer than theirs. but honestly its up to you, im not pushing anything on you but I think your getting a great deal on either of these units.
btw, dont listen to these guys about you tank being overstocked. If it works and theres no problems then your doing fine. if you fish fighting or having serious water issues then you may be overloaded. just my 2 cents... good luck either way.