River Rock from Michaels safe to use in aquariums?

[Psylant]

Hi guys. I bought a few 2lb bags of large river rock to use in my aquarium. I filled up a bucket with water and dumped all the rocks in it. They've been soaking for a couple weeks yet they seem to leave an oily film on the top of the water whenever go to change the water in the bucket. Has anyone used these with any type of success? They look really cool!

 

[HackJob]

try the vinegar test...if it fizzes would not use. Try changing the water more often.

 

[fishwhisperer]

you could bleach all the rocks, then soak in water with extra dechlorinator

 

[Psylant]

It would pass the vinegar test with flying colors. Bleaching may be an option. I think it's something that they used to polish the rocks. They seem almost slimey. I change the water daily.