So i have built a terrarium for some red eye tree frogs that I will be getting soon. currently i have just gravel as a drainage layer but was wondering if I could use horticultural charcoal instead. I know everyone is using the hydroton but I don't like the look of it in the terrarium and I cant seem to find it locally. everywhere i go has the charcoal and was just wondering if this would be a suitable substitute. any help would be greatly appreciated.

thanks
wes