Hi, I was going to try to reduce the flow in my aquarium for my future betta fish. I have a hang on back filter with a waterfall output. So, I was going to try to do it by putting a soap dispenser and some river rock underneath the output, but the only one they have in my area in Chrome otherwise I have to drive a half hour. Do you guys know if chrome (as in the metal) is harmful to betta fish? Thank you! Here is the basic Idea except they used plastic and marbles...