Looking for some help with my holding tank. It will not pump out. So far I have done the following work with no avail. removed and replaced the vent so that it is shorter and more direct, making it a streight line to a deck vent( it is not clogged). I have removed and replaced the plactic fitting and in the process got about 2-3gallons of liquid dumped( no sludge). I have replaced the Y cvalve and verified that the hoses on the input side are clear ( plan to replace when tank is empty).Attempted to have tank pumped out by service twice this year and at least once each year for the past two years( i now know it was in vain). Attempted to pump out at pump out station, again no luck. Tried to use macerator pump but again no luck. It seems that the problem is on the outbound side of the tank, and I beleive that there is some type of stopage at the exit port.(have checked the hoses and they are in tack). NOW FOR THE QUESTION.......IS THERE ANYTHING I CAN PUT INTO THE TANK THAT WOULD SOFTEN OR REMOVE THE STOPAGE??? CAN I USE A HAND SNAKE TO ATTEMP[T TO FREE TO PORT???? AM I DESTINED TO OPEN THE TANK AND MANUALLY CLEAN IT OUT?????? Would like to finish this three month project this weekend if possible so any information would be appreciated. bobcat