VERY bad idea to save liquid to make more room for solids. Without a LOT of liquid those solids cannot be emptied. After going a month and a half without putting water in the tank you are most LIKELY in a position where a POWER FLUSH will be required to clear out the blockage. Find someplace that a "honey wagon" is available to come out and power pump your tanks out with their high pressure system. WATER is the MOST importent item for keeping your black tank working properly. Not enough water and you're in trouble. That is why you NEVER dump a black tank that is only partly full. You NEVER leave the black tank completely empty while in storage and you NEVER skimp on water use when using the black tank system. There is absolutely NO reason that the tank needs to be emptied sooner as long as it has plenty of water.
Good luck / Skip
