I decided to use a slurry additive when I encountered problems with smell and sludge.
I applied the SlurryKing to my 80,000 gallon above ground circular slurry store when I was fattening pigs. Previously we'd had problems with at least two feet of heavy sludge that wouldn't shift without a lot of power and blasting. We applied the SlurryKing and when we came to empty in the autumn, the slurry literally ran out - like gravy.
A noticeable reduction in smell was an additional bonus – very helpful as we have some large and expensive residences not far from the farm.
I recommend SlurryKing to anyone with slurry to manage - it takes all the hard work out of it.