Backyard Aquaponics
A place to discuss aquaponics

Dr J,

That is a problem that we saw a while back when RF was unable to differentiate between hydro and aquaponics (HEY, YOU GUYS, GO BACK TO YOUR ROOM! NOW! "Sorry, guv! We was just out for a stroll when we heard the word!" "Yeah, we didn't mean nuffink by it...") However, this is a pretty easy fix, as you have done, by labeling one "inorganic" hydroponics and the other as AP. I'm with you, at least.

I am not sure how an open loop system could use less water, since, by definition, it has water leaving the system. One of the intrinsic beauties of AP is the limited water use of the system, the nutrient cycling and filtration via plants, and, it appears to me that an open loop would loose nutrients out of the system, as well as use more water.

What advantages do you see, joel, if any, to an open loop system?

BTW, the place looks NICE! I haven't peeked in in a few months. Lots of growth here, and a tonne of info. It's really nice to see what is happening here. Onya!

C

just for the record, i use my system as VB does. Semi-open, though VERY mildly semi

This is the way i look at it, i have a small dirt garden patches running from time to time. i use 20 to 50 litres via buckets to water these dirt patches. I then top up the system with either rain or tap water, with the aim to be rain when ever possible.

This gives me two distinct advantages;
1) the dirt patches are receiving nutrient rich water (much keeps asking me for more fish water for her plants)
2) Many of my concerns over accumulation of certain dissolved salts are taken care of my topping up with fresh water.

I figure i'f i'm going to use water on my dirt patches anyway then i might as well effectivly "put it through" my AP system. Adds to the synergy of it to me.

Steve

I think we need a different set of terms for open/closed. Perhaps cyclic use vs sequential use.

How could sequential use less than cyclic? Very simply - sequential can be demand driven by the plants (smartvalve, capillary, electronic, waterpots), whereas cyclic chugs water around all over the place and every open surface of water is more evaporation. And as I said, making pumps and electricity also uses water. Not using either would thus save water!

My own system is currently a cyclic-sequential hybrid - I circulate some water through a bog garden, a living wall and a rockface, and take other water out for ground irrigation.

njh,

You have any photos of your system? That sounds very interesting!

Not yet, I'm working on a BPOP then I'm going to put it all on a website for everyone to pick holes in and tell me I'm an idiot etc. My goal was originally not aquaponics, but rather for regulation of a traditional greenhouse for propagation of rare plants(something I'm very good at), but I realised that I could use the water profitably for fish production, and as I said earlier, fish poo is great for plants!

Hahahaha, that makes sense! I look foorward to seeing it. I like picking holes in things... glad to help!

Used aeroponics and or ultrasonic foggers as a propogation tool? Got any words of wisdom regarding these? There was a school of thought that they are good for propogating, but not good for established plants in aeroponics, something about the fog not carrying nutes with it. Makes sense if the fog is a true fog (ie consended vapour) as dissolved salts would be left behingd. Thoughts on the matter NJ?

Yes, it seems like we're on quite different tracks... Though part of the reason I cycle my water so often through the system is to allow the bacteria growing on the gravel to convert ammonia into nitrates and to allow the roots of the plants to extract it.. I think we're talking quite different types of systems.... I'm talking about system's with heavy stocking densities of fish and these require the water to be pumped through the grow beds reasonably often, otherwise the fish will suffer from poor water quality..

yeh fair point EB, the planting medium is both a biofilter and a mechanical filter.

NJ, not detracting from the meagerly usea of water via other means, but a flood and drain can be quite efficient if the entry oint of the water AND the flood height of the bed are an inch or two below the surface.

aeroponics is something I'm planning to try when I get some spare dough. I've heard that people have successfully struck eucalypts using aeroponics - eucs are notoriously hard to strike otherwise. If it doesn't work, well a fogger in my bog garden would look really cool I think

Ok, tonight is craft night, I shall bring along my BPOP and see where I go.

sorry if you've already said it but what is BPOP?

Yeh foggers have been used to strike notoriouslyt hard cuttings.

Big Piece of Paper. I knew someone would have to ask

I think there is no such thing as a completely open loop aquaponics system IMHO. Once you break the chain you are left with an Aquaculture system with fish or whatever, and essentially a hydroponics system which is using the waste products from the aquaculture. It is only when the system is closed can It become an aquaponics system. A so called symbiotic relationship occurs when both the fish AND the plants are supported by each other... Fish make waste, gravel converts wastes and filters out particles, plants feed off watter, water returns back to the tank, fish make more waste...

Plus without water being returned to the tank, how do the nitrates build up the tank in the first place to feed the plants. I don't know how efficient our little nitrifying bacteria friends are but I don't think all the ammonia can be converted in just one pass through the growing medium, with out separate biological filtration running all the time.

Tim, i probably wouldn't have been as definative as you but the one thing that does tend to support your view is Dr Sav's observation that a MATURE (1 - 2 yo) "closed" AP system had an "unknow" growth promoting component. Has been theorised here that it is a complete balance of micro flora and fauna in beds / tank..................

ANYWAY................i think all that been said about "closed" Vs "open" has been said.

Each to their own and best of sucess with which ever method you choose.

It all about synergy and sustainability and i think that ALL the proposed systems from "closed" to "open" to "semi-closed/open" qualify.