Peggie, Obviously storage of human waste is a huge issue and getting worse. Is it possible to buy a lot of just the bottom half of a partable toilet (the storage section)? I found in using one that the bottom half seals very well so you can transport it to a dump station. So why not just buy say five of the bottom half and on extended cruises it provides equivalent or greater storage capacity than a holding tank. I used to use a five gallon bucket with a locking lid, when the storage tank was full I would empty it into the bucket and lock down the lid thus getting another 5 gallons of time between dumps. This is a potentially messy job with spills and is unsanitary. Using a lot of bottom sections they can be stored in a lazerette until a convenient dumping spot is available. Any comments? I'd hate to have to buy the whole toilets just to get the bottom halves. Thanks, Dave