Sump building material thickness

  1. LWormy Member Member

    Hello! I am thinking about building a sump that is 25 inches long, 5 inches wide, and 19 inches high. I will be putting lava rock, gravel, and sponges in it. I will also be planting lucky bamboo (which is a bog plant) in the sump to act as a nitrate filter. This sump will be filled to the top with gravel and lava rock, so there won't be that much water in it. I am planning to build a box out of plywood and line it with pond liner. I will then cut holes from one side of the box and build a waterfall from it. The water pump will pump water into it so it will basically have the same design as a HOB filter. The pump will pump water into the middle of the sump and water will go out from the 2 ends as a waterfall. I am not sure what the thickness of the wood should be. Any ideas? I will be gluing everything together with aquarium silicone. Is there any better material to build it out of other than wood? It have to be cheap and easy to obtain, since I am not exactly rich. Help is appreciated!
  2. matsungit Well Known Member Member

    You can buy Lexan or polycarbonate sheets from the hardware store. Prices vary depending on thickness. You have to learn how to cut it though. Youtube videos help.
  3. Claire Bear Well Known Member Member

    What about precut acrylic sheets with an acrylic cross bar for support and use aquarium or marine sealant/caulk to attach?
    I think you may be disappointed with the wooden box sump but maybe not-I just don't have much faith in pond liners as I have had a few fail.
    I would love to see the finished product and how it works when it is completed!
    Good luck! :)
  4. LWormy Member Member

    Hmmm, I haven't thought about acrylic sheets. Will I be able to get it in Home Depot? it is the only store I have excess to. Also, aren't they expensive? I thought that acrylics are pretty high priced. I am looking to do this project in less than $50. How would I cut it though? I only have a small saw and a metal clipper. But nobody had answered my question yet: how thick do the wood have to be if they are held together by aquarium silicone?
  5. ryanr Moderator Moderator Member

  6. LWormy Member Member

  7. ryanr Moderator Moderator Member

    Umm, that's plastic in the link, not acrylic.

    Check out for some great info on sumps. He makes most of his from acrylic, and there's heaps of info.
  8. FiscCyning Member Member

    That link just takes me to corrugated plastic, which wouldn't be strong enough for your project. If you go with glass it is surprisingly easy to cut. You can get a glass cutter for only a few bucks, and my Home Depot does sell those.
  9. LWormy Member Member

  10. FiscCyning Member Member

    I believe you will need at least 1/4" thick, but someone else should verify as I've only worked with glass not acrylic. Either way you will need thicker than that, since .093" is less than 1/10 inch.
  11. LWormy Member Member

    Do you know where I can find acrylic that thick?
  12. FiscCyning Member Member

    I would call Home Depot to see if they'd sell it at your store. Sometimes the store inventory is different from what they list on the website. A sheet may exceed your budget, but it is worth calling to check. Someone else may know of another place to buy it cheap.