RogueProeliator wrote:...That might be a considering for that one extra pipe/zone I laid in the back near the pool for future use...
In that case... a bit more info.
On my skimmer base, well below the water line, there was an unused stub for connecting a pipe. I drilled a small, ~3mm, hole in that and then ran a short horizontal pipe to an elbow and then up to above the water line. I then placed a cap over the end of the pipe, drilled a hole in the cap to let the switch hang down. It took a bit of calculating and playing around to get the height of the pipe just right to match the length of the switch stem. By connecting to the skimmer as low as possible, and keeping the connecting hole small, it damps out most of the wave action (caused by wind or people) and keeps the switch from thrashing too much.
I just used a simple level switch, like this
At first I planned on having two switches, high (full) and low (refill) water marks.
You can find some products with two switches on the same stem, like these
However, in the end I found it worked just as well to check if the pool is low once a day (I.e. is the switch is off?) and then refill until the switch operates. This also eliminates any chance the pool will refill while my sprinkler system is on.
One note though, you want the vertical pipe (I think it is actually called a sight glass or tube) intake to be far from any suction. Otherwise your water level might be impacted. In fact, we had a problem this year. The pool refill cycle ran the full maximum 20 minutes and over filled the pool a bit. At first I thought the switch had failed. But, it turned out we had tried a new cloth filter (thinking diaper) that covers the skimmer basket. It had gotten so clogged with dirt (spring storms) that the suction from the pump was holding the water level in the skimmer about 10cm below the true level.
BTW, for Korey: Fortunately,. at the end of our pool where the skimmers are located (the deep end) there was no decking, just a planter. So, digging down was not an issue.. But, with a bit of ingenuity, and some luck, you might be able to mount some type of switch in the skimmer itself. You'd need to deal with wave action and dampen the signal in code or something. But, there are small switches with the float ball on an arm, sort of like an old toilet refill valve. Like