Backyard Aquaponics
A place to discuss aquaponics

In trickle feed you tend to get water channeling so you really do have a wet/dry situation and most of your media is not being utilized to greatest effect. Essentially, you have only a fraction of the bio-filter effect of a system doing flood and drain in the same size grow bed. Plants like trickle feed but it is not an efficient way to provide your system with bio-filter.

Constantly flooded can be done, we have members who have been doing it but there are a few added challenges since the grow beds are not getting as much aeration as they would in flood and drain the bio-filter capacity seems a little more restricted and one must be vigilant of problems with plants that don't like wet feet getting root rot.

Flood and drain seems to give the best wetting of the gravel while still letting air get at everything in turn which seems to provide the best bio filtration, solids filtration and happy plants. Also, worms survive very well in flood and drain gravel beds (and probably in well aerated flooded beds) which allows solids to be broken down in the beds rather than ever needing to empty and clean out the sludge.

IF you really want to do Aquaponics with something other than Flood and drain media filled grow beds, it is worth looking into adding some separate solids filtration and bio-filtration. (The constantly flooded beds might be an exception to this but I'm not sure how they are managing it and think our member who is doing it successfully might have some special magic talents )