Modular ballasts of an aquarium comprise a lampshade and a plurality of ballast modules, wherein a reflection plate and a plurality of lamps are mounted inside the lampshade. The tug has a bow and the barge has a notch in a periphery of the barge. Furthermore, the memory controller is configured to perform one or more write-read-validate operations to calibrate a clock-cycle relationship between the data-strobe signal and the clock signal, wherein the write-read-validate operations involve varying a delay on the data-strobe signal relative to the clock signal by a multiple of a clock period. By comparing the spatially subset spectral reflection of rooftops to a reference spectra, the rooftop type and condition can be accurately assessed.