Jonathan, it is a pleasure for me to share what I think are sound concepts in aquaponic functioning, but I do not think that it is the only way to do things. The following pointers, however, is what my thinking is based around:
1) Nitrification bacteria likes to be in close contact with the water supply that contains ammonia, have good oxygen supply and are light sensitive. Coating them in muck is not going to aid nitrification, as you will likely reduce their efficiency. Thus in its purist argument, nitrification is a "second stage" aquaponic process after most of the solids have been dealt with. Muck and plant roots in the end influence the path of water through a bed, and thus, I believe, your nitrification area does not remain the same in a heavily planted gravel bed as it would be in a sump full of floating media of the same dimentions / surface area as the gravel bed.
2) Mineralization is a "first stage" aquaponic process to me, synergistic to worm activity. Both worms and mineralization processes can be housed in the same environment, and a contact area between the media and the water supply is not as critical as in nitrification.
3) pH balancing and gas balance. It is not always the best of ideas to try and add acids or bases or buffers into a fish tank or a filter, thus having a space where you oxygenate / degas and can add your pH buffers is not such a bad idea.
In many home system designs, people try to reduce clutter and components but for the same reason as a fuel injection engin works a bit more efficient than a two stroke, I think that paying that extra bit of attention and infrastructure in setting up multi-stage filtration will pay off.
Jonathan Farrand said:
I have much to add to my system!! This info is spot on for where I am at with aquaponic plumbing and having different elements of filtration. Thanks Kobus!
Eric, my main concern is that you are creating a situation where you are confining some of the oxygen depleting reactions to the fish tank. With most of the solids staying there, you are in effect mineralising and nitrifying in the same environment that the fish must respire in - thus three sinks for oxygen. Plus ammonia and nitrite generated inside the fish tank...
We clean the fish tank, partial water change and vacuum fish waste, about every 60 days. We'll be moderately stocked, so we'll have less trouble, hopefully. Oh yeah, and aeration will be there plus I'll try and integrate duckweed.
Kobus Jooste said:Eric, my main concern is that you are creating a situation where you are confining some of the oxygen depleting reactions to the fish tank. With most of the solids staying there, you are in effect mineralising and nitrifying in the same environment that the fish must respire in - thus three sinks for oxygen. Plus ammonia and nitrite generated inside the fish tank...
This is the drawing about what is known for the filtration aspect. I don't know how the NFT will be added. The fish tank (FT) is a 40gallon or 50gallon barrel. The height variation in the design is to show it's slanted. The system will be built by 15 people in my bio/chem class--most of which recently learned what aquaponics is one week ago or less. Anyways I hope my bad drawing skills don't get in the way.
Without knowing if the pump is in the borttom of the barrel...