Your system is still relatively new correct? If so, give it some time, after a while as more bacteria & other stuff colonize all parts of the system, including sand, it should stay in place a little better. When I first started up my tank I was a little obsessive about having the substrate 'just so'. No powerhead issues, but I soon found that various critters, Maroon clownfish for one, would rearrange it to their liking, not mine. I now live with whatever the system decides to do with the substrate, as long as there's no sandstorm, which there is not.
|