Backyard Aquaponics
A place to discuss aquaponics

traditionally in hydroponics the airstone is directly inder the plant as far as i understand. This ensures o2 saturation of the water around the roots.

What i am getting at is that if you have enought air being pumped into the water then by default the water around the roots will also have maximum saturation.

Garry?

this is what I am hopeing for Steve with my lettuce as the airation in my system is good, but I do not have a air pump fitted yet

Hi guys, just something I happened to come across that might be relevant:

http://www.actahort.org/books/440/440_36.htm

This study looked at the effect of DO in hydroponic lettuce nutrient solutions and concluded concs as low as 2.1 mg/l gave vigorous lettuce growth.
Using a home testing kit, I found that my aquarium runs at about 7mg/l and my ill-fated continous flow mini aquaponic system ran at about 10mg/l.

would i be correct in assuming that your doomed aquaponics system was running at a lower temp than your aquarium? see the chart below for 100% saturation mg/l verus temperature.


http://www.courseworld.com/bio/envir6.html

Yeah, aquarium's near a S.facing window (Northern Hemispere!) and the AP system was on an N.facing outside wall.

can tell from the saturation mg/l

You DWC noobs. I've been DWC for years you only had to ask.

Massive aeration on both plant and fish side. Venturi nozzle aerates water as it goes to plants. Waterfall aerates as it comes back.

ten times circulation (total system volume minus fish tank volume) per hour = growth faster than ANYTHING I've ever seen.

It's like nft in that, the plant is in a planter but most the roots are not. The roots are fully suspended with LOTS of room. 5 gallons per tomato anyone.

I'll grow some more this summer and show y'all how it's done kiwi style.

I have a really good idea of what is required now, thanks everybody. Somthing I am interested in - and I guess it gets back to the thread of leaching of chemicals from plastics etc - is what sort of containers should one be looking for from B or wherever to use as reservoirs/growing pails for this type of setup. Can you tell from the recycle code on the bottom what it is made of (e.g quite a few have the # 5 recycle code, what does that mean).

Food grade buckets with lids are an obvious choice for a DWC system of course, or if you wanted to grow a massive plant, maybe a plastic barrell. I have a couple of the green type with black lid (160 litres I think). Could grow me a big tomatoe plant in that one using dwc .

Sure could. The real trick as stated is the dissolved oxygen. By increasing the flow into and out of your plants in DWC you increase the oxygen utilising the venturis and gravity.

There can be many problems, if not looked at correctly. I'll start a DWC thread and discuss some.

Infact vb tomatoes are very commonly grown dwc.

.Will definitelly look at giving it a go Steve. I suspect the new DWC thread will be popular (for a while at least)

I have had quite a bit of experience with DWC.

In an aquaponics scope i wouldn't like to use it as the only growing media unless you have other mechanical filtration, as the roos will wuickly clog up from the fish poo. Either have mechanical filtration, or better still intergrate it into a system with a gravel bed.

AA would you agree that floating raft and traditional "in the bucket" DWC are essentially the same IF a floating raft system has 100% O2 saturation?

I would definitelly be looking at it as an addition to, not replacement for, the gravel grow-beds.

Funny that you ask that Steve. Check how I opened the DWC thread.

I never cared that solids were in the roots. Pump em in and let the bugs sort em out.

Won't work in NFT but DWC there was never a root problem once the correct recirculation rates were found. I'd open the bucket there was lots of floatie bits but it was just floc, the roots were red, and so is the fish food...

Fair enough AA, seems like fast water change out is the key.

SO how about the floating raft DWC comparision i asked about?