If the budget for your system keeps you from buying weighted hose...you will pay more than the difference in labor and frustration. I have read where folks have used other types of hose (PEX & garden hose) and then weighed it down with bricks, cinder blocks, sand filled garden hose, rebar, etc). Popular opinion suggests not skimping on the weighed hose. I can tell you that pulling the diffusers up for inspection, cleaning and relocating is pretty easy with weighted hose. I can't imagine the line having bricks zip tied to it! It's not hard to keep a DIY hose weighted down, it's just not that easy getting it in place and moving it if need be. I have moved all three of my diffusers in the last year trying to perfect their operation and pulled them up twice for inspection and cleaning.

I have not heard of anyone suspending the diffusers from a float. That could ave some benefits, but you will now need an anchoring system to keep the float from moving around the pond and it does not eliminate the weight needed to keep the diffuser down (or the hose).

Fish on!,
Noel