Well, dont take my word, but I'll try to explain how mine is set up.

Like you said, it is installed next to the coping, but it's basically a cyliner (about a 6 or 7" pipe which is connected to the pool with a piece of 1.5" tubing.

The level in the cylinder is identical to the level in the pool, and has an overflow tube (just like your toilet), which can be adjusted in level... so when the pool exceeds the level, the water overflows into the tube and out a drain.

This seems like it could easily be installed via the skimmer also.... but perhaps he is considering just installing a straight line?

Mine also has a water line into it, so that it injects water into the pool when a float drops too low also. It also uses the same assembly as a toilet for this task also.

Either way I guess, if he comes off your skimmer, what determines the overflow level is how "tall" the overflow pipe goes. The water isn't going to drain out until the water level exceeds the "level" of the highest part of the "drain line".

Pb's feel free to correct me if I'm wrong.

By the way... I guess he can access the exterior of your skimmer body w/o tearing up your decking?

The downside to an overflow either under the coping or in the back of the skimmer is that it can become blocked with debris. An auto leveler like the one stevenbr describes (I use pool miser) does not have this problem and the fill and overflow levels are adjustable.

My neighbor has a in-skimmer overflow. Every time we get a heavy rain, the small 1' lines clogs, and the pool over flows. Even if it is kept clean, the 1' just isn't big enough to deal with the amount of water being captured.

Our pool has a 'OverFlo' (brand name?) pipe installed just under the coping. It's a 3' round pipe that had been flattened to form a 1 1/2' tall by 5' wide mouth. That pipe, in turn, connects to the in-deck drain system. Even with the severe down pours we've had from time to time, the device has never been overwhelmed, or clogged.

The picture below is of the overflow. It is just to the right of dead-center of the picture. Installed just below the coping.

Jeff

Here is a link that might be useful: OverFlow device

I have a 1.5ish line that is just under coping, just at the spot on the tile that pool should be it's fullest. It leads to a line that drains our yards overflow from the gardenbeds. I cannot imagine having that much debris in my pool that would clog that little hole. At least it has never done it yet. I would think a large hole would have greater chance of a leaf getting stuck in there.

I personally do not like the asthetics of the huge overflow fittings. Even here in seattle w/ all of our rain, the 1" standpipe in the poolmiser is sufficient to keep up with the rainwater. Since the pool miser lets water in the side of the pool wall, it's not likely that debris can enter the pool miser chamber and clog the line.

Racket - I couldn't help but notice you are from Seattle. My friend in Seattle is looking for a pool contractor to replaster and retile his pool. Any suggestions?

Thanks

Have him e-mail me @ rob@aqualinepoolandspa.com

I have the same overflow drain as afnajs pictured. It works great, hooks up to the deck and planter drains and drains to the street. We've never had a problem in the rain.

Some cities do not allow pool water to drain to the street drains, so a different setup would be necessary in that case (it would have to drain to the sewer). Our drains go to the ocean so some cities are very strict as to what can go in there.