Backyard Aquaponics
A place to discuss aquaponics

I'm trying to come up with an aquaponic system design that suits my needs and I seem to be coming across some inconsistencies in what I'm seeing and what I've been told. Currently I have a media-based ebb and flow system and along with a number of things that I've been told along the way is the necessity for the right amount of media as well as the right depth of the grow bed so as to ensure a good nitrification process. Now I'm looking at the nutrient film technique and while I have seen a couple systems with grow media filters it doesn't seem to emphasize or require grow media. I find that a bit perplexing considering the emphasis that I've seen people put on grow media. Can someone unravel this for me?

in essence you need something to complete the bio-filtering - ie. host the bacteria responsible for the nitrification process.

media is one option, and common to aquaponics (and one of the easiest to implement).

if you look close enough other filtering / biofiltering methods are used, but typically they require some understanding of the system and the efficiency of ammonia conversion and waste removal.

If you run a system with just a fish tank and NFT there will be some nitrification but it may not be sufficient to process your systems requirements. Also NFT and DWC generally require filtered water as plants do not do so well when crud and bacteria grows around the roots. As you read a few other threads you will also see that dirty water, bacteria and fish are not a good combination - the fish generally die. So filtering works for both the fish and the system.