Well it's far from a 75g. Dovii dude has posted many times that it is a 125g. It looks like a 125g. For those of you that really need to know that MFK sticker is approx 2" high at the "M" and 9" long. Use that as a comparison, and you can tell the tank is 21~22" high and over 5 foot long.
BTW I had a 150g that was 21" high, ofcourse it was 8 foot long. Yanker could it be your dad's tank is 8 foot long?
