Internal Fluidized Sand Bed

[Torrean]

I have an idea for an internal "sponge" filter. For examples sake let's say we are working with a plastic fish food container. Cut a bunch of small holes in the top of the filter...then cut four small holes around the outside near the bottom... next cut a hole the size of some standard air line tubing in the top. next stick a piece of air line tubing in each of the four holes around the bottom and silicone the pieces into the holes to make a seal. Silicone the air line tubeing to the upper section of the fish food container so that the open end of the tubing is above the lid of the fish food container. Next you put a piece of air line tubing through the lid and put a long flexible air stone on the end. Coil the air stone until it fills the bottom of the fish food container. Next fill the container with sand...not sure how much, this would take some trial and error. Now cut on your air pump.

Theoretically, the bubbles will churn the sand. Water would flow in through the airline tubing that is attached on the outside of the container, then up through the container and out through the top. You could put a piece of sponge over the sand to prevent sand from floating out through the top of the filter.

So what do you guys think. Does this make sense or do I need to clarify/draw a picture. I'd love some feedback. I'm planning on attempting this pretty soon and I'd like to get as many perspectives as I can before I waste time and a little bit of money on this.

I know that a bubble rock can churn sand effectivly because I changed my girlfriends tank from gravel to sand without thinking about the bubble rock. I just buried it in the sand and it worked just fine...It does lift sand into the water though, which is a problem I am working on.

 

[andywg]

It could work, though I fear the problem will be having a path for the wwater to get in that does not allow the sand to get out.

I'm not sure if you mentioned having it, but you could do it probably with just one (providing it is tall enough) by having a contrinaer, and in that container having a tube in the middle that doesn't quite reach the bottom, above the level of the tube have an air stone (or a few) and then have the bubbles released through the top.

If you got enough air pumping throught the bubbles and the water flow may stir up the sand, though I am unsure of how successful it would be.

I would recommend trying it in a non stocked tank as a proof of concept first.

 

[Torrean]

well it worked...sorta. The sand get's stirred up by the bubbles and it is contained by the filter media on top of it, but the tubes that are supposed to draw water into the bottom of the sand bed were a complete failure. When I cut on my filter one of the tube started spraying bubbles out, then it started squirting sand. I removed them and now it is working beautifully...although I have my doubts that it will be an effective filter because I'm not sure how the water circulation is going inside the container. The water can get in through the top and I'm sure some of it is cycling down to the bottom of the sand bed but I don't know how much...the ammonia tests will tell all I suppose.
I tried to get some ammonia today so I could experiment but everything either had surfactant, chelating agents, or quality control agents...whatever that means. I went to 4 stores and no pure ammo. I bought the quality control stuff...I'm gonna call them sometime tommorrow and ask what the agents are and if they'll be harmful. I'm very interested to know how much ammonia this thing can deal with. Once I get some results I'll start fiddling with it somemore. I might try to make it more like a sponge filter like you suggest with a larger center tube that the bubbles rise up through but I just don't think that will work because the sand will just compact around the bottom preventing much water flow.

I may end up giving up on the sand and attempting to use very small pieces of clay (fired of course) That was the original plan but my girlfriends bubble rock under the sand made me want to try this out. Well I hope it works.

 

[OohFeeshy]

If it's a tank with no fish then I wouldn't worry about chelating agents or anything, it's not going to kill any fish becasue there aren't any.

 

[Torrean]

well there will be fish eventually. Once I finish experimenting with this I'm planning on stocking the tank.