I read my last post and there was an unintentional pun that the aeration experts probably are rolling their eyes about.
I said this... The 'bottom line' is that.....
Yes, keeping the line on the bottom is critical!!
The compressor, its air supply and its housing or protection to keep it cool is the part that is worth spending money on to get a good one. After that you can source your own tubing, design a manifold if you want 2 or 3 separate air lines although probably not needed in your scenario. You can buy the diffuser membranes and use standard PVC plumbing to attach to a base. Several threads show examples of ways to support the diffuser heads so they don't tip over and so that the plume is raised sufficiently off the bottom to not stir up mud.
