Squirrels tore up the covers on my my outdoor chair cushions gathering up acorns. I was going to just toss them out but got the idea to try them in a 55 gallon barrel filter. I put 2 layers of of the batten cushions, about 10" total and 2 layers of 1" sponge cushion foam and still have room for more but I am thinking about putting plants on top. I just started it up this afternoon but so far it seems to be working like a charm. I'll have to see how well the batten cushions rinse out, I already use the sponge cushion foam in my skimmer and waterfall filters and it works great, they catch a ton of waste and rinse out easily.