Underwater Syphon Effect?

Only the hose above the waterline will empty (with the pump off). Whether the pump can pull hard enough to refill the hose depends on the pump type & rating and how much air is leaking.

The hose will drain to pool level.

You will need to assure that the hose remains in the suction socket, at all times.

If you do that, you should be fine.

Yes, I probably will have to put a weight on top of the skimmers lid.

I would think that you would want to disconnect the barracuda in between uses, so that your skimmer is allowed to clean the surface.

That is precisely the setup I am using.

I have mine cycling on and off using an X10 digital timer system.

As long as the intake to the scupper (skimmer) is below the water line you are OK.

If your hose end that goes in the scupper has a graduated (conical) fitting, see if it is removable. If it is, my guess is that the actual end of the hose (sans fitting) is a blunt end. Plug this into the scupper hole and your system will work better.

I used to have a 1 HP motor which worked so so. I upgraded to a 1-1/2 HP motor and everything works much better.

Barracudas normally have a small valve at the skimmer which permits top skimming action to occur simultaneously with the cleaner operation. It is imperitive that this valve is below water level because if air is sucked into the pump, it may lose prime (depending on the amount of air entering) and may not be able to recover that prime. The water in the pump will eventually boil off and the pump seals will likely be damaged. The connections to the skimmer must be airtight or below water level and the hose must also be airtight to prevent loss of prime.

A slight loss of water in the hose when the pump is off will be readily recovered when the pump starts providing there are no major air leaks in the system.

Before connecting the hose you need to fill it with water, it will then float with the top of the hose at the water surface, and it will then remain full of water unless someone lifts one end of it out of the water.

All good points by fellow cuda users. I use a timer also to run my filter and the sweeper so I learned this one. If you are going to control the sweeper with the timer make sure you check it when the pump shuts down for the day. What will likely happen is the water from the pump/filter unit will flow backwards and pop the cone fitting out of the socket in the skimmer. So the next cycle starts off with the sweeper fitting not seated. You could install a check valve at the pump intake to prevent this. It will also help keep the suction lines primed for the pump. I have NOT done this as it would prevent me from winterizing the lines in the fall unless I would also add a threaded union to allow breaking the line. To me that is just one more place for more maintenance so I have not done this.

All this talk about timers I want to point out I would not have a pool without a timer. The wife had an above ground pool when we met and no timer. Can't tell you how many times I had to drag my tired self out of bed and go outside to make sure the pump was turned off.

A weight, (stone etc) on top of the plate/cone in the skimmer box will hold it down when it shuts off - my brother in law had the same issue, that was his fix - simple and it works

We keep a rock in each of our skimmer baskets but I never tried to weight down the sweeper hose cone fitting.

If the hose does empty and fill with air, head for the patent office immediately, you have the makings of a perpetual motion machine.