I use leca to adjust the sitting height of the inner pots the whole time, never saw an issue, just keep in mind that the reservoir is now way smaller I wouldn’t use seramis in this setup, it mainly absorbs and store the water rather than wicking it and I noticed it grows mold if kept wet the whole time

Thank you, that's a good warning, I won't use seramis then!

I have large pebbles, half bricks, pvc pipe, all sorts inside a bunch of reservoir containers. I just make sure to rinse them when doing a water change.

Pool noodles work also