I have a 6’x2’x2’ tank and bought this as it was the largest size I could source. However at just less tha 4’ long it doesn’t light the tank as well as I’d like. I could have gone down the route of doubling up on smaller tubes but this is hassle & more starter units would negate the cost / environmental savings of LED tubes. There have to be plenty of other 6’ tanks out there so come on Arcadia, please make at least a 5’ tube !!