i'm probably wrong but they resemble limestone to meThanks for the info George.
Just another question if you don't mind answering.
Those rocks used in the scape, what are they?
I've been trying to find rocks almost exactly like that for one of my tanks but cannot find a trace of them.
In Iwagumi tanks, an external filter and heater are used so as not to clutter up the tank. If you watch the vid, you can see the glass filter inlet/outlet pipesJust a Q but how did you hide the heater, filter, etc? or are they just removed for the pic?
The rocks are Mini Landscape Rock, supplied by Aqua Essentials. They're also known as Seiryu Stone, supplied by ADA.Those rocks used in the scape, what are they?