| Luke, if you want to move a lot of water and exchange a lot of oxygen with little amp draw, look into paddlewheels. There has been a lot of aerator engineering and testing for both sewage treatment and auaculture. Here is a quick summary from some of Claude Boyd's work at Auburn:
AERATOR TYPE KG OXYGEN TRANSFERRED PER KW HR
-------------- -------------------------------------
paddlewheel .................................................. ........ 2.2
propeller-aspirator (e.g. Air-O-2) ............................... 1.6
vertical pump (what you found at Memphis N&T) .......... 1.4
pump sprayer (shoots water in the air) ....................... 1.3
diffuser (air stones, diffuser plates, etc) ..................... 0.9
Akai, a popular set-up is:
bottom drain -to- vortex settlement
vortext -to- pump -to- kaldness moving bed biofilter
kaldness -to- bead filter for fine solids removal -to- pond return
or
kaldness -to- TT for gas exchange -to- pond return
I have low fish density and am cheap, so I use:
bottom drain -to- settlement chamber
settlement -to- pump -to- TT
TT -to- pond return
Has only about 4 feet of total dynamic head.
Why are you stopping at 4.5 feet deep? That's about what I have, but I wish I could go to 6-7 feet. You could get half-again as much volume in the same footprint. Of course, your site may have some logistical or engineering constraint to going deeper.
steve hopkins |