You should probably check out the suface agitator aerators that are commonly used at fish farms. Here's a link with pricing and operating costs http://www.dunnsfishfarm.com/kasco_pond_aerators_61_ctg.htm They're not really a decorative fountain but purpose built for maximum oxygen transfer. I would also compare to the shallow water diffuser systems. For small systems, operating cost differences betweeen bottom diffusers and surface agitators seem minimal.



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