I'm setting up my 35 gallon long tank and I already have 3 bags of expensive plant medium which is quite fine in particulate size. The thing I'm trying to figure is how I can use the UG filter by covering the filter plates with a fine meshed material of some sort, and possibly even using silicone to glue the edges of the material to the sides of the tank. I want something I can gravel vac over which is both durable and is thin, so gunk doesn't get stuck in it like a filter pad. I know there are those who'll say it shouldn't be done, but I think it can. I love undergravel filters with an attached power head, and I want some water flow to go through the gravel. I only want to know of a kind of material, like cheese cloth, or fibreglass woven cloth, or some other good material for this purpose, and where I can find it. This will be a planted tank with small fish and other creatures such as shrimp, and I'll be able to grow the plants that require more light as I have a VHO set up already bought and a huge canister filter Don't bother trying to tell me it can't be done. It can and I'll do it.

maybe use window screen material... at lowes or home depot? also, maybe try a pool supply store, they might have screens that go over filter equipment that are submergible

That's still too big. this needs to be way fine. I don't need to have very high flow in the gravel, just a little. I'm thinking of a material that is thin as paper,(is white and shiny in my imagination) has microscopic holes, is synthetic and super strong.

there is some material that my LFS sells some thin stuff that's like 200 micron or so... i think they sell it at drs fosters as well... maybe a layer of filter floss...

I like the 200 micron filter floss stuff. I think that's what I want. I wouldn't use a bed sheet because I would think it would wear out after a while. I think the filter floss is super thin and strong and shiny. Right? What do people use it for?

i dont think filter floss comes in sheets, just clumps, and u break off how much u need... people use it in their filters to trap particles and stuff, kinda like what the filter cartridges are made of. I picture it getting dirty fast and stinking to high heaven... and i imagine it being very tricky to work with underneath substrate IMO.

i would imagine a media bag cut into sheets would be best... maybe find two large ones, cut them at seams so its spread out into a rectangle and use a few, they dont cost too much.