Not toilet humour...

Yes Napisan is used in caravans and cassettes are best emptied after 3 days whether full or not. We also find that a road trip before emptying ensures everything is disolved and pours out easily.

The capacity of the cassette means it can be used more during the 3 days but I would not use capacity to delay emptying. After 3 days is when smells etc seem to arise

Alan

Empty our every 2 days otherwise if it is to full, it gets to heavy. At 2 days, it does not smell that bad.

Best thing is to use it as a toilet for both number 1 & 2 as they smell more with only urine.

We use a cap of soaker a day.

Probably exactly the dame Odog. Our built in Thetford has a standard 20 litre cassette. If used full time it needs emptying after three days; not too heavy to handle, and what ever sanitiser you use three days is enough. See My Blog on Toilets and using Sodium Percarbonate laundry/nappy soaker powders.

HI all, having had 'porta-potties' camping and with a trailer tent, 2 cassette based c/vans and one M/Home, overall the years- smell seems to be noticeable by end of day 1 or 2 with using proprietary chemicals as much as with napisan as your chemist says, if its mainly urine waste. ( temperature dependant of course) .
I personally found an into bowl spray ( you'll love this one!) called 'poo pourri', royal flush, to be good. ( NO relationship with them of course) toilet spray. Ex USA, buy here easily. works by using essential oils .
Napisan worked fine in all our bigger vehicle cassettes. we emptied as filled or by day 2 - 3. disadvantage- subject to finding a disposal point.
many articles and blogs on subject of toilets, Napisan .
by the by: ?not so funny - saw the result of hot weather on a full single type site loo once- exploded in very nasty fashion! OH .... one would say!
MG.