I currently have a 29 gallon freshwater aquarium. I use sand substrate which as I have learned kills your filter. I have been through five Marineland Penguin Bio-Wheel filters, the sand just eats through th impellers which scratches the housing and ruins the filter. What type of filter is suggested for this kind of setup? Any filters in particular? I was thinking about getting an aquaclear but wasn't sure if they would have the same problem, as they are both power filters. Do I just need to get a canister or something? Are pre-filters effective, any that you can suggest? My budget is $75. Also, it would be nice if it had a compartment for a heater. Thanks in advance.