Lava rock to hold LECA down.

[MateoinLosAngeles]

Anyone use lava rock on top of their S/H pots to hold the LECA down when watering?

I've been using small lava rock and small river rocks, however, I've started to see some roots avoiding the pot and I wonder if the small size of the lava rock might be blocking some air out of the pot.

I'm considering trying something else like maybe big river rocks, bigger than the LECA, just to make sure there's sufficient space for the roots to grow into and for the air exchange to run smoothly.

Any other alternatives?