Invincible I have strugggled with bith large and small media, I have found that it really doesnt matter what you start with you always end up with the small eventually, I guess just a part of the stuff melting at some point it get small?
I run a deltec but its and older one, the new ones now have the sponge (like yours I assume) to catch this fine particle. This small media dust seems to be the bain of the reactor cloging up from time to time. I have a little trick I learned to clean the reactor of this stuff, I am not sure if it works on the unit you have but it did a great job on my deltec. you disconnect the input line and put the output line either outside or to the sink, then hook up the input line to the tap faucet that your RO/DI unit is attached to. then just run the unit as normal with out the co2, with the tap pressure and the circulation in the reactor it flushes the media of any of the overly fine particles.
On the media front I got a price on the material listed above at $.16 per pound, I will get a shipping cost on Monday hopefully.
Mike