I would like to set-up my planted tank with both a soil substrate and sand. When I see this being done, it looks like cardboard is placed between the two in the initial set-up then it is removed. It would seem that that would make for a real pain keeping them seperated. If not I would love to know how that works.

I was thinking of making up 3 inch wide longs strips of acrylic and using them a a permanent barrier between the two substrates. Would this work? Has anyone ever tried this?

Well, using less soil substrate is one way.
I've seen screens used, but roots muck this up when you replant.
Some just leave the root stumps and replant tops.

Regards,
Tom Barr

I was suggesting a similar solution to a fellow Swedish aquarist yesterday, so I'm very interested in the results if you do this.

It sounds very interesting for those that wants a low-tech (soil+gravel) but also an open space with sand for Corydoras.

I did this with my tank when seperating peat moss and gravel from my sand area. I used Lava Rock as the barrier. Looks nice IMO.

Here are some pics of the process:

Spar,

Did all you use was lava rocks? Have you had any mixing of the substrates yet? My big concern is over time (such as 6 months to a year) I would have alot of mixing. I do not want to redo my tank every 6 months.

Quite a few folks do this, and nice option to keep it well planted: use floating plants over the open regions and maintain their position by directing water current.

Low light/nop CO2=> great place for the floating plants. You do not need to worry about the plants below because it's nothing but open unplanted sand.

This looks nice and it's also rather natural looking.

Regards,
Tom Barr

all i used was lava rocks. no mixing yet, but my Val has spread across underneate the rocks causing some unfixable mess.

if i could do it over again I would have stacked broken slate instead. I like the look of the lava rock though. maybe just do 2" of slate stacked, and then the remaining layer with lava rock (if you like the look). Keep in mind that some lava rock floats though.

I've used stacked slate with success.
Nice look too.

Some folks have used slate skree as a substrate, looks pretty cool and is much different than what most folks ever add.

Regards,
Tom Barr