Is this so that a pot can be set inside at a certain height? Or are you wishing to plant in it?

You could use an upturned pot if your wanting to put a plantpot inside...

hi i have updated my question with more information thanks

hello. look around for a plastic bread tray that has the plastic mesh base, easy to cut to size and has no effect on the water or plants that you are using,
ogon.

A plastic aquatic basket upside down, or those plastic storage boxes in DIY stores, both of which come in all sizes
Have you got a wire basket from an old fridge or freezer?
Careful its a rust free metal or plastic coated though.
I dont think an upside down plastic cutlery box would give you enough height?
All come with lots of holes so the water would circulate better than a solid box.

i see what your saying i think . you want the lilly at the bottem and marginels on top . ive used galvanised chicken wire in my water fall to hold the charcoal of the bottem so the water can sercullate underneath . i grow watercress in there for a filter . my water is clean enough to drink and oxygen lovers like my 3` sterlet and my 5 poundish rainbow trout as well as the others are fine and have been for about 12 years so i cant see a problem with your idea at all . heavy metals are a big worry but not galvanised chicken wire it seams . i have some blogs of my pond or you could look on utube under nosey potter and see it running if your interested .

hi, well now ive seen your pic i know who you are as i live in thetford too. i have, on various web pages, seen such a wire shelf but i cannot remember where or maybe it was a american page, nevertheless this is what gave me the idea of a wire shelf. nice to know that i could use wire as long as galvanised. i will put a pic on my page when it is done. i must just remember to make sure i can cut a round piece with no sharp edges as my next job is to line my 1/2 whisky barrel. i have a smaller barrel which i will use for a couple of goldfish. this idea of water cress is interesting, can you tell me more about it as i will have no filter in either pond....hopefully.just a small pump in both. i will make a circle of about 30" which will rest on the sides of my 36" barrel, so no fixings. dont know if you remember the wire tray that sits on top of a wok, it will be along those lines but in a grid pattern, great pics. thanks chrissy

hello fellow thetfordian its a small world lol . water cress likes running water but is about the best biological filter you can get with the benefit that you can eat it ofcourse . it likes sun to but apart from that its realy easy . it will root from every juncsion with leaves or shoots . just go to tescos buy a bunch and put it in . it needs know planting infact its the roots that make it partly such a good filter . you can cut it into little bits if you want or just put a bunch in the moving water on the top and it will do the rest . its getting towards the end of its best this year as it flowers quit early in the summer and doesnt do much after that thow its so cheap you got nothing to lose apart from a few pence . if you want to know anything else just ask . im just going to look at your profile . ps if you see me and you cant miss me feal free to say hello . im the one with a large skull tattood on the back of my bald head lol . bye for now .

i know what you mean about the wok idea and definatly be carefull with the wire as its very sharp . it mite be worth getting some cylicone and putting a dab on the end of the sharp bits . you could use it to glue the shelf in but i guess youl want to take tghe swhelf out periodicly again bye bye lol .