[sub]Sissy I'm talking about sand to put on stone bottem, but they say is the best to put nothing because is easier to clean,my pond is all build of cement and after that I set the volcanic rock at the bottom and all around,it looks great but I thought this because of the cement pond is colder than the pond witch is made without cement only dig hole and put pond linar, so I think to put sand or something else to be warmer.Can you advise me more fish, I said that the pond 50 cm deep, which could take what we advise, as far as all the plants I learned about pripremio.malo me to write the English tend to go so sorry for that.[/sub]