Cement

The cement was going to be used for a backround in my new tank, do u think this is safe. It's base is polymer, as i said earlier
 
Yes, it is water safe. Polymer refers to hydrocarbon chains fused tightly together to form a chemical bond. Plastic (of al types) are polymer. They are impervious to water and will not release any bad molecules into the water.

GB Chemical Engineering! :)
 
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