Backyard Aquaponics
A place to discuss aquaponics

I must really be getting good at this nagging thing. 10 years of practice up my sleeve and look what happened this weekend!

2 x 4500 L tanks buried 500mm. I have a u-shaped growbed made of stainless being fabricated as I type and plans to install decking in between the "U". This is more exciting than Xmas when I was 4.

Ok so this has been a lot of effort. Can I ask everyone honestly, all things going well, will vegies really grow at 4 x the speed of conventional growing?

Bugger the image won't add no matter how much I edit it using my iPhone.

Pics or it didn't happen as they say on the interweb

I'm afraid somebody has been yankin your chain!

Yeah, it's at least 5 times !

I don't know "how many times" stuff grows faster in AP. It depends on how you look after the plants growing in dirt.
If plants are not watered often, AP plants could grow 100 times faster. If you water plants 4 times per day they might only grow 1.3 times faster.
Sometimes for some unknown reasons, probably due to nutrients, plants grow faster in dirt.

I know that plants like basil and spinach etc get leaves that are about 4 times bigger than they get in the dirt.

All I can say is they will grow!! I used to try so hard in my dirt garden and would be so excited to reap some pitiful excuse of produce,fighting watering restrictions,weeds,snails and cats. Now i get home from work ,all has been taken care of and all i have to do is feed my fish. As for 4xfaster,hell yeah,they have water and nutrients delivered every hour! They are alive and growing with little effort!!

Sounds wonderful. How do you get stupid iPhone pics to upload? Keeps telling me its too large so I crop it and crop it again and it is still too large.

So the overall consensus is that they do not grow faster or they grow faster and bigger. I'll take a mean score and assume they grow at double the speed and a little bit bigger lol.

9000 L total of fish tanks

Yippee! How many fish you got?

And how many litres of filtration you got in your GBs

Yes I was looking on eBay for a sump tank for a bath set up and chanced across some second hand water tanks. Was a bit of a rash decision I know but the rest is history and I've been wanting to get into aquaponics for years.

I have no fish yet, hopefully growbeds will come this weekend and scoria. I have only 3.8 m3 of growbeds. I guess I could either get more beds or just half-stock the tanks. I am getting 100 trout for this season and I'm hoping that with all that extra room in there they might grow a bit quicker.

500litres of filtration= 25 fish Maximum. How much filtration do you have? It is your filtration that will allow you so many fish!

3.8 m3.... is 3,800 L ... of grow bed....

@ 25/500L.... that would be a max of 190 fish....

Well I aint no Mathematician so Thank goodness for the ones that know.Thanks Rupert

Hang on you have 25 fish max/500 litres filtration there Rupe WOW!!
No I would say 25 fish per 500 litres filtration/1000litres water

Sizing the tank and grow bed by number of fish can be deceptive, it is probably better to size tank and media by the fish bio mass. Your optimal number of fish per L or water and grow bed depends on species and intended harvest size. You cannot use the same ratios by number if you intend to harvest fish at 700gr vs 2kg. While you can increase effective stocking densities with additional aeration/feed/water flow the load capacity of your bio filtration is always a limiting factor. The general rule as I understand it is absolutely no more then 15kg of fish per 1000L of gravel media assuming you feed them to saturation. Fish bio mass/bio filter ratios in excess of this can create water quality issues.
Initial fish stocking densities can be 2-3 times higher though since not all fish even of the same species grow at the same rate, some will eat more and grow more rapidly then the rest and they are ready for harvest sooner freeing up bio mass capacity for others to grow.
4x growth rates are not the norm (that would depend on the quality of the soil you are comparing it to), though when you take into account the greater growth densities and longer growing season in AP systems achieving 4x the growth per meter sq is attainable from what I understand.
BTW you do NOT want to start a new system at it's maximum filtration bio-mass, it takes time for the bacteria to develop to control ammonia/nitrite, 6 weeks is minimal to start good development and it takes up to a year for a system to be fully matured.