Backyard Aquaponics
A place to discuss aquaponics

Theoretically......
If I had 20Ha of vines that will use about 100ML of water, predominately over the summer months. How large of a flow through fish farm could I build, given that the drippers run every night for 3 months or so, 500-750KL per night, building up and tailing off for a couple of months pre and post harvest?

I know this isn't aquaponics, but it is where my AP journey started a few years back and I intend to blend my musings in with the 'DWC' thread started by TCL and any info I can gather on NFT (the most logical synergy it seems) to come up with plan that might work.

Perhaps what I'm really looking at is an AP system of a significant scale, that has the ability to increase production over the summer months, coping with the extra nutrient load by 'flow to waste' (winegrapes ). A continuous water exchange should help regulate temperatures downward over summer, but I'm not sure how this will help.

It's just some thoughts I've been chucking around in my head for a few days. Paper and pencil after dinner. Bugger all on TV these days. Perhaps I'd be better off getting a movie out than dreaming about how to best blow parts of millions

Not addressing your questions so much... as raising another...

Given the usual usage of pesticides in a grape growing enterprise.... how would you expect to be able to maintain fish??

two best wines I've ever tasted come from vineyards that "don't irrigate", not that I know anything about wine, or irrigating vines

some crop other than vines might work better

Perhaps you need to look up some Recirculating aquaculture system info to see how much water change would be needed for a particular situation of fish and extrapolate that to how big a fish operation would be needed to provide the change out water to irrigate the desired amount of vines. Since flow through with water is definitely not very compatible with aquaponics it is probably best to come at it from the RAS point of view with sufficient bio-filtration to keep the ammonia/nitrite in check and the flow through to take care of nitrates and feed the vines.

We barely use any pesticides. We go through a fair bit of sulphur and maybe some copper this year if it's wet. We use round up only for the weeds, so no sprayseed or pre-emergents. If there is no recirculation from the vineyard, drift is the biggest potential issued I'd have thought and in a lot of situations your neighbors might be the end of the idea.

We have some non-irrigated vines in the area, what with the water restrictions and all. You probably wont notice them now, but by christmas time, they'll be the ones without any leaves. Probably pushed into a heap. Then again, we don't grow anything likely to described as "the best wine I've ever tasted"
Your point about crop type is a good one though. A crop, or combination of crops that use a more constant supply of water would likely suit better.

How much nitrates do you want to get to the plants. And are you going to be able to drip the solids out to the vines. I'm playing with an idea for growing lettuce in nets and watering the garden. It uses ABF's to do most of the bio and a swirl filter to keep the solids in one place so they can be watered onto the garden or to satellite pots.

Duff, I'm interested in how you are going to do this. Been thinking of drawing water off the DWC AP to send to smart valves built into wicking beds (giant auto pots). The DWC AP water will be reasonably free of solids, but will filter it anyway so the valves don't clog. So a float valve to keep the water topped up in the AP, a tap in the DWC tank to a line and filter which then branches to the wicking beds, which will be topped up as needed by an auto pot smart valve is what I am planning. Yeah I know, a bucket to the wicking beds would be easier - but it wouldn't be automatic and much less fun to set up!

Dexter K, your idea is worth exploring. Running a summer fish like silvers form now until harvest in Autumn might be possible. Filtering out the solids is a given in recirculating systems, so some draw off after solids removal would require little if any filtration. I guess the irregular water requirements of your vines vs the regular need for draw off for the fish would need to be addressed. So perhaps an alternative crop is called for. I plan to draw off from tanks that are using a large dam as a biofilter and feed the nutrient rich water via drippers to a fooder crop. The plan is to drought proof the stock side of the farm. Tagasaste is the fodder tree I plan to trial, and 2,000 arrive in about three weeks. Will be fed to sheep, cattle, pigs and chooks.

Is regular water exchange undesirable in AP?

Not undesirable, but if the system is working well, unnecessary. That's because in addition to the bacteria doing their job, the plants are also extracting nutrients so there's less chance of nutrient overload.

But it could also be that in AP if the water exchange was too great, the plants would not thrive due to nutrient dilution. It's all about balance.

The concept I'd come up with over the last week or so, basically boils down to an AP system that best suits a commercial scale, that can then be heavily stocked during the summer months, with a controlled bleed off and top up (water exchange) system to cope with the excess nutrient load that the AP system can't handle.
Or you could say that it is a flow through aquaculture system with an aquaponics filtration set up to maintain water quality during winter months when the water usage and therefore the flow through drops off.
I think I just said the same thing twice?

Sorry.... but that's a two summer, with an intervening winter.... grow out...

The smart valves are fun toys. You can also use one container with a valve and have this one connect to several other ones. Then one valve controls the water in the rest of the containers. I have chillies going into a setup like this.

The value in a non cloging bio filter for a farm setup is that once the fish load has been removed(harvested) then the bacteria can still be used to process urea and seasol etc until the next lot of fish. Out this way they just empty a 1ton bag into the water but it does not get fully converted.

Water changes in small systems are not really needed. But using a little water for the dirt garden gives a small water change and could help if the plants are not using everything equally.

Silver Barramundi obviously

It of course depends on the type of "commercial" operation you are going for. Some operations have actually found that they loose money on the fish and the money maker for them in the Aquaponics system is the veggies. They are running raft systems in a slightly cooler (though still tropical) climate than UVI though. With a raft system the planting can simply be adjusted down for winter when the fish are not producing enough nutrients to keep the rafts fully/heavily planted. In media based systems with the solids breaking down in gravel beds, the nutrient load is evened out more and the nutrient drop off is likely to lag behind when the fish slow down or are removed.

So I guess the questions is, what are the goals? If it is to provide nutrient rich irrigation water for fields, then so be it. If it is to grow a particular amount of fish then that is different. And to have an Aquaponics system that is balanced and thus wastes minimal water that is yet another thing. So you will likely do best designing you systems if you clearly define the goals first.