Originally Posted by turner_landscaping
Wow gone a few day days and the thread blows up.. there's is no reason to pour concrete in the bottom of the basin a way over kill. If you are really worried about settling add some crush 411 in the basin bottom and compact bout 2-4 inches worth. I hardly ever use perform basins I custom build all of mine using liner cinder block and heavy abs grating. I build these water features every day I've just got done building a 1250 pound bubbling rock feature. I have bubbling features that have been in for years and haven't settle. I've have a 2500 pound bubbling granite boulder going in a few weeks. If you search my threads there is a pic of a 1 ton bubbling rock that I've posted on here and has never settled as well. Pm me if want.
I have always liked your use of the ABS grating in lieu of the matrix blocks on pondless features and it evidently also works quite well for you in load-bearing applications. In my area, however, because of the sub-soil being predominantly very sandy clay, everything eventually settles unless some form of base is laid to provide a sturdy foundation and evenly
distribute the weight of the structure being built. I have seen houses, walls, sidewalks, patios, swimming pools and even ponds that have settled over time.
I admit that this influenced my recommendations for a concrete base in this thread, but I have become, over the years, conditioned to be cautious.