Backyard Aquaponics
A place to discuss aquaponics

i cant find jack on the search function.

so anyway, air pumps or falling water? or both? i want to acheive the highest DO level.

i'm considering building a floating bed sys. with styrofoam floats.

if i do, do i want the floating bed before or after the gravel bed?

thanks guys.

Floating bed comes after the gravel. If it goes before the gravel, all the fish crap gets stuck to the plants roots and cause rot.

Watt for Watt, I belive that a 20 watt air pump moves more water than a 20 watt water pump. Especially if combined with an air lift.

Yep, definitely growbed before raft....

I always recommend an airpump, preferably with battery backup... as well as falling/return water to aerate...

And if you're planning to run a raft(s).... then you'll probably need to aerate them as well... so an airpump with a minimum 4 outlets is probably what you'll need... depending on size of fish tank and number of raft beds...

You can never have too much aeration...

A really good way is to use a Venturi injector on the outlet from the pump from the Sump to Fish Tank. If you want to use an air stone, use a fine rather than coarse. More bubbles, smaller and overall higher surface area... but they take more pressure to drive them.

I use a venturi.
The return tube from my 'under pressure' pond filter stops just above the water level. It is shrouded with a slightly larger tube that goes all the way into the water. It is capped at the top and has holes in it. Direct injection of bubbles and much quieter operation compared to simply dripping.
Two considerations, no backup battery for the pump, water level cannot exceed certain height. But so far so good for me.
I really need one of those backup battery thingys.

You certainly do.... no power... no dripping... no venturi... eventually, and possibly sooner than you might think in hot weather... no fish...

Whatever means you employ... IMO, an additional air pump, with battery backup is essential...