i forgot to post about your ground fog.
Typically what you need to do is cool down fog as quick as possible.
The reason many are so expensive is because they quick cooling airconditioning system in a portable machine.
So all fog can be ground fog.
many people would put dry ice in a foam cooler and blow fog through one end and let the cooled down fog just flow out the other end, but that gets pretty messy and I've heard dry ice can be dangerous to handle.
So the invention of low lying foggers were created.
its a fogger with a big chamber to put standard ice and sodas if you want.
The Ice chills the fog and then you have Low lying fog.
Antari makes a unit called ICE. and its a big enough machine to hold a good amount of ice. ADJ makes a Mr. Kool which works the same but has a really small ice chamber.
Now the problem with using reg fog fluid is that great fog fluid is made with a great hang time. the longer the smoke lasts the better, but in this case you want a quick disapating fog fluid.
The minute the fog starts to warm up and want to rise, it disapears. So you can imagine you will be going through fog fluid really quick.
Hope this helps... i'm really not sure of any other machines out there other than Antari ICE and AMDJ Mr. Kool