For the paludarium that I'm building (http://www.monsterfishkeepers.com/forums/showthread.php?t=324353&highlight=paludarium), I'd like to incorporate an overflow that will allow for easy adjustment of the water level in the tank. I'm thinking of a design based based on a simpler modification of the overflow I proposed here:
http://www.monsterfishkeepers.com/forums/showthread.php?t=321136&highlight=skimless
To reduce the amount of plumbing this one will have two 1.5" bulkheads (for redundancy in case of a potential clog) feeding into a 2" vertical pipe via reducing Ts. This will rise up to a T and 90 degree elbow which will be connected to a run of flex PVC leading down to the sump. I've included a quick sketchup drawing below to illustrate the idea.
This is the same principle as one version of the DIY overflow (in the stickies) except it uses bulkheads and therefore won't need priming.
The water height in the tank will be determined by the height of the top T and elbow. Trouble is, I'm not sure where exactly the water level will be when the pump is running (top of the T, bottom of the T, somewhere in the middle) so I'd like to allow for some adjustment. To accomplish this I was thinking of incorporating a telescoping/expansion coupling into the vertical rise between the bulkheads and the top T, which will allow me to adjust the height of the T.
http://www.flexpvc.com/cart/agora.cgi
Has anybody incorporated one of these telescoping couplings into their plumbing? Do they work well? Any thoughts/concerns (potential leaks etc.)?

http://www.monsterfishkeepers.com/forums/showthread.php?t=321136&highlight=skimless
To reduce the amount of plumbing this one will have two 1.5" bulkheads (for redundancy in case of a potential clog) feeding into a 2" vertical pipe via reducing Ts. This will rise up to a T and 90 degree elbow which will be connected to a run of flex PVC leading down to the sump. I've included a quick sketchup drawing below to illustrate the idea.
This is the same principle as one version of the DIY overflow (in the stickies) except it uses bulkheads and therefore won't need priming.
The water height in the tank will be determined by the height of the top T and elbow. Trouble is, I'm not sure where exactly the water level will be when the pump is running (top of the T, bottom of the T, somewhere in the middle) so I'd like to allow for some adjustment. To accomplish this I was thinking of incorporating a telescoping/expansion coupling into the vertical rise between the bulkheads and the top T, which will allow me to adjust the height of the T.
http://www.flexpvc.com/cart/agora.cgi
Has anybody incorporated one of these telescoping couplings into their plumbing? Do they work well? Any thoughts/concerns (potential leaks etc.)?
