Backyard Aquaponics
A place to discuss aquaponics

Always something to keep in your mind when going "green". Sometimes the extra complexity needed is not so green. Look forward to a squiz at your results whatever you end up doing.

Grow bed media serves as a home for both plants and nitrifing bacteria, and as such is a vital component to what most of us are doing here (or in my case attempting to do).

Due to the forgiving nature, and to a large degree self correcting chemistry within an aquaponics system, most of us are lucky enough to have no real problems with our chosen grow media.

It is likely though that one media out performs others, and this would be very useful to have studied in some form.

Questions revolve around how much difference a large surface area or an irregular shaped media make to the housing requirements and subsequent populations of helpful bacteria.

A general norm in this forum seems to be a ratio of between 1:1 to 1:2 fish tank to grow bed given a density of around 3 kg of fish per 100 litres. Stocking density seems to be based more on the available populations of nitrifing bacteria rather than anything else. Its therefore possible that a smaller grow bed requiring high nitrates (say growing tomatoes) might be able to cope with a greater amount of fish production if the media was some high density bacteria housing rather than the potential villas we offer with our current media. Smaller systems might allow for better cost management when it comes to heating and real estate requirements. Which in turn may allow for the growing of out of season crops and gaining a higher market price (I realize that's not of particular concern to you but still important to the industry)

gravel is inexpensive, tends to stack flat and be rather smooth
scoria costs more and sucks to work with, but has a massive surface area
clay balls cost a lot and are a poor shape shape for max surface area but under a microscope have a better surface area than most gravel

It would be great to know how much difference the media makes to a given volume's ability to process fish waste.

I think there may also be questions around micro anaerobic areas and their surprising benefit.

Yes, and no... we need to be careful when trying to simplify the inter-relationships...

A smaller growbed, by definition... means less volume of whatever media... granted a higher bio-filtration density might compensate... and there has been much work done on determining "supposed" areas of different media...

But our growbeds provide more than just bio-filtration of ammonia... serving to trap sedimentation etc...

Smaller volume... means less sedimentation capture... and the possible need for other solids removal systems...


I haven't heard of any real benefits of "micro anaerobic area"... certainly not within a growbed... unless you're referring to JP's RSG filter to convert/lower excessive nitrates... and/or possible off-gassing...


What benefits are you referring to??

Those were meant to be questions worth asking not things I know the answers to. Generally speaking I think some testing on media and its waste processing ability could be worth a student taking a look at. I suspect there are some potential inventions in the grow media area that might come to light if you poke the subject about a bit. I'm actually working on this myself so I know there is at least one idea out there (not as a money making thing but more a process and a media a developing nation might find useful)

Ill try to re find the stuff I read on anaerobic areas but because the science was a bit over my head I didn't note it. Ill go back through my browsing history and see if I can find it again. It wasn't from BYAP but was in some paper on wetlands.

-craig

Kewl... be interested to see what it's about... ta..