Looking for ATO for a new tank

I'm looking to get a 6 foot tank, found a few that are 100-150 gallons. My current 75 gallon loses quite a bit of water a day, but I can usually manage filling it up manually a few times a week. With a tank that large tho, I think it would be best to get an ATO. What is the best looking set up that won't break the bank for a set up like this? The tank WILL NOT BE DRILLED so there won't be a sump to pump the water into. I have seen a few and tried to do some research on my own, but I'm not sure if the larger tank means I will need a different type of ATO or just a larger pump. Thanks for any help you guys can give me!

Michael