OMG i feel like an idoit i miss read your post marius im glad i went back and checked for some dumb !@# reason i thought u said 5lbs of salt not sand..DOHHHH....im so glad i check id have killed my fish for sure haha so ill go to the LFS and pick up some aragonite sand and put it in it wont hurt any thing if i put more will it i have two under gravel "caves" for my cichlids and they love it and i dont want to lose them so if i were to get say ten or 15 lbs that wouldnt change any thing would it?