substrate question

[ericbullock]

Hello - I've been steadily aquiring all the necessary components...and I'm
getting ready to light this candle! I've got the substrate heating cables
layed out (I've gotta use 'em after all the hassle I went through to obtain
them!), and the Flourite has been ordered. I recall someone mentioning
something to put between the sand and the main substrate to keep roots
from getting intertwined in the heating cables. What was it again?

Thanks so much for any advice...I can't wait to get started! Next on my
list is a good place to source some really cool rocks.

-eric-