Adjustable height overflow using telescoping coupling

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the_deeb

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Apr 22, 2006
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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.)?

overflow3.jpg
 
The only problem I can see is that it seems like it would provide another likely area for a leak. I haven't used the telescoping couplers before, but I'd be afraid they wouldn't stand up to constant use like they would be subjected to under your scenario.
 
I have used them in potable water systems with no problems. Given the relatively low pressures seen in aquarium filtration I imagine they would be just fine long term, at least in fresh water applications.
 
So after taking a look at the expansion couplings at Lowes today I've decided against using one, mostly because these fittings are huge! I don't really want to take up that much space behind the tank. Also, I think the water level in the paludarium is ultimately going to be too low to effectively utilize this setup. So I think I'm just going to use this overflow design with regular plumbing.
 
i used one for my durso standpipe, but it's inside my overflow box and submerged in water. they are bulky, but it worked great for my application!
 
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