Some of this depends on how much water flow you need, like how much water you need to get out of the pool to supply a water feature. That said, just to do the job of a skimmer (get surface waste off the water) one placed in the proper location for you location should do the job. A professional should come to your yard to see what other factors may be there that may cause you to want a second though.
No as long as the skimmer section of the pool is properly supported like the rest of the pool
You pour it slowly into the skimmers and it stays in the filter
You should have two valves: one for the skimmers and another for the bottom drain. Close the valve to the bottom drain. One of your skimmers should have a rotating disc which will cover the intake at the bottom of the skimmer intake hole. Rotate the disc. In this manner all the suction from the pool pump will be at the one remaining skimmer. Attach your cleaning hose to this remaining skimmer while vacuuming the pool.
use something else wet
If you have a top skimmer basket the water level should be at least an inch above the basket, so you are not sucking any air. They seem to operate more effectivly at removing floating material BEFORE IT SINKS if the level is about half the distance from the top to the bottom of the skimmer opening.
Get a better pool skimmer normal pool skimmers usually don't do a very good job of cleaning rubbish from the surface of a pool so try a floating pool skimmer have a look on www,dragonfly.biz
Salt is added throughout the pool not the skimmers.READ THE MANUAL AND THE SALT BAG CONTAINER.k
Absoltutely not. The pressure underground will lift and crack your pool. You should lower the water to below the skimmers and do a full pool closing for the pipe system. If you don't know how to get the water out of the pipes and filter you must call a professional. Most owners do it themselves but be sure to learn the proper technique.
Getting toys in the pool skimmer can make keeping a pool clean a hassle. There are skimmers out there which have bumper guards on them. The bumper guards will push larger items like toys away from them instead of scooping them up.
Try another method of killing them.
Check the grid and manifolds for holes or cracks.
A small electrical current is passing thru the salt water an it seems that the negative eletrical charge is passing from the skimmers being plastic an its possible from the spinning vortex created by the water pumps sucking are creating the positve electrical charge which is small but just enough to react with the salt in the pool an based on many studies with the larger negative charge an the small positive charge turned the water orange