What is the recommended way of cleaning things inside of the aquarium? I know that typically you don't "clean" things, but I purchased a tank from another person and there is buildup on the suction cups for the powerheads, so they won't stick to the glass. Any suggestions? Also, do I need to clean off the stuff that has collected on the other equipment like the heater or powerheads? I know this seems trivial, but I want to try to avoid as many problems that I can and if the buildup that has probably partially died at this point spikes my tank in a bad way when I set it up, then I need to know what to do to avoid that or if I even need to. Thanks!