>>We have adopted two red ear sliders and we're getting them set up. I was wondering if it is ok to put small chunks of concrete and/or cement in the water. I just built my home a couple of years ago and everytime I put a plant in the ground, I come across these chunks of rock that look like dried up chunks of construction debris. Can I use these in the tank, or is that risky?
I would think it'd be ok as long as there aren't any sharp edges on the chunks, they are large enough that they can't fit in a turtles mouth, and as long as you clean it all very well before using it. Soak them in a bleach solution of 9 parts water 1 part bleach to clean them. Then rinse well and let it all air dry for a day or so.. that should clean it for you.
I've bought rocks that had sharp edges in the past, I used a big metal industrial type file to smooth those out, worked great.
-----
PHRatz