as far as cleaning the glass goes, i dont know about isopropyl, but DENATURED ALCOHOL is the best cleaning agent known to man, and very very overlooked, and will not harm the EXTERIOR of your tank in any way, including the seams. as far as the gravel vacumming goes, i may look into buying a smaller size vac, in my old 10 gallon, i usually got everything vacced and still had water to spare before i got to my 25% mark