Backyard Aquaponics
A place to discuss aquaponics

Instead of working with clay beads that float you may want to consider lava rock or River gravel. Just a suggestion.

The clay beads shouldn't "float".... it suggests that you're flooding too high...

Some of them clearly have a closed cell foam structure and will apparently float indefinitely- one Canna clay ball I threw into my FT 6 weeks ago is still floating just as well, although now in the sump. However, none float in my GBs as the water stays below the surface, and no doubt the river gravel helps stabilise the flooded ones.

Perhaps it would help if rephrased: clay beads shouldn't float when weighed down by the recommended inch (25mm) of dry media.

Another solution would be to get a 55 gallon drum and fill the drum with the clay balls. Then top off with water and add a round panel and weight it down check it periodically till you get no floating. Also stirring them up on occasion should release trapped gasses.