hydroton as an aquarium substrate

I was playing in the new 2 ft with using hydroton as a light fluid substrate for aquatic plant growing.
This involved making a linked tank system to compare growth rate in a typical tank to that with hydroton - but sharing the same water column.  After making the mods to the feeder tank - testing with different return pumps I added the washed hydroton. (Cleaned it in the bath)

After leaving it for 48 hours to soak in the tank I still had two layers. Floaters and almost sinkers. As soon as you added current they would all move around.

Hydroton does not make for a great substrate if you use it exclusively - mix it and it could be a plant saver.

Now I have 30 kg of hydroton - best I get serious about hydro culture ...

The tanks have been converted to a connected system - 1 for fish stock - the other for plants. circulation is done via an air-lift.

BTW added the hydroton as the initial layer to the 2ft tank - placed a net over it then added an inch of gravel ... seems to work like a charm.