[Aquattro]

I've used mildly deep sand beds over the years, no issue. But my last tank, set up pretty much the same as the ones previous to it, had the sand solidify in about 4 months. I mean solid. I took the 24x48 inch sandbed out in about 7 pieces...I never figured it out. I have 2 inches of the same sand in my current tank, no issues in 18 months...