another idea is using large diameter PVC, would be easy to put together and would not look as bad as bottles, this can also be safely painted with krylon fusion paint of your choice.
Yes That is definitely an option if one wanted to really improve the idea. I like the idea of seeing inside the filter media. I plan on using a mixture of carbon/small pebbles, cut up small sponge cubes, and maybe ceramic cylinders. And I think using the "Smartwater" bottles wouldn't look bad. They are just a plain sleek cylinder unlike most water bottles. I would love to make this using glass bottles but I have no way of drilling holes in them, plus they'd probably break.
I will probably use the bottles because they're like $1.50, are uniform/same size, see through them and sleek, and it's just more practical for me. Plus the pvc that comes in large diameters is not that cheap really. Well, I'm a cheapskate thrifty nerd. What can I say? Haha
I'll upload pictures soon, maybe even take step by step pictures if anyone wants to attempt this or improve the idea for their needs.