Great ideas, Thank-you for adding pictures.

What size pvc do yoy guys use?

I'm wondering about the glue used to hold the pvc together? any problems with it breaking down, or being in any way toxic to the tank?

Then I think we're all in trouble because I'm pretty sure most use PVC/PVC glue to plumb there tanks... only difference is the outside of the pipe is wet too... would you even need glue??

um, may be a stupid question - I'm pretty green - but I guess I'm just wanting to make sure that everyone is using the normal pvc glue and that there's not something I'm missing here...

I built a couple of stands in my tank for some rocks and to help create some caves, I used PVC and cut some egg crate to fit over top the support so I could put rocks in the middle of it and then used zip ties to hold it together.

I followed a similar approach, used 1/2" pvc for the vertical lengths (with threaded ends and fittings rather than glue, for ease of later design changes ... never changed it, so I'd just recommend going with the glue approach as plain pvc parts are cheaper), and 3/4" pvc for the long horizontal lengths.

Here's a look at the cave I built:

2 shots of the structure on the the test bench:

http://pansy-paws.com/aquarium/images/IMG_3131.JPG

http://pansy-paws.com/aquarium/images/IMG_3132.JPG


2 shots of different versions of the cave:

http://pansy-paws.com/aquarium/images/left_side.JPG

http://pansy-paws.com/aquarium/images/IMG_3237.JPG

I used white plastic ties, which quickly blended in with coralline algae :wink:

Wow, I never really put much thought into PVC structures, or seeing pics of the neat cave work you can do!

There will definitely be pvc caves in my next tank! :)