Backyard Aquaponics
A place to discuss aquaponics

Hey CG:
I think you have enough fish to grow that amount of lettuce. I had about the same amount of fish last year and grew a lot more than what is shown in the pictures. How fast is the lettuce growing? I would think you would almost see the growth from day to day when things are humming along. Are the lettuce plants getting enough water flow to keep them cool and wet?

CG, can I have some bricks?
That's a great stock pile!

Our floating lettuce etc is doing the lack of poo thing. The older leaves are yellowing and the new leaves come in green. Hurry up silver perch!

its the new leaves that are coming out yellow and the plants are not growing at all, i fed a handful of aqua-max pellets a day

Janet, that's a great article thanks for posting the link.

i am thinking the best place to put rusty nails would be around the pump's input? maby?

how much nails should i use 15 - 20? or a sheet of rusty galvanize in the water. or even and old 20mm galvanized pipe i got lying around that would give the fish something to play in as well

I don't think Iron (II) oxide (rust) is a) water soluble, b) plant available. Galvanised metal is coated with zinc, aluminium, cadmium and the various 'rare earths'. Not what you want to be dissolving in your tank. If you want to add iron, use iron chelates, in tiny amounts.

with chelated iron, EB uses 1 to 2 spoonfuls a month in his big tank, mixes it in his sump tank from memory.

Yeah, I think NJH has a point. Go with the chelated iron.

any iday of good iron chelates?

I put some nails in there for the heck of it.

I was wondering the average temp is 29c i i got the pipes in full sunlight could it be getting to hot?????

i think lettuce wont grow as well when their root zone is that hot.

try a little chelated iron first, no sense making heaps of changesall at once

I read somewhere that peopel would burry old cans and bottle tops; and as they rusted away it would add Iron to the soil. Took a long time but they said it worked. And rust can't be that harmfull to fish seeing as how they seem to like to live in old ship wrecks.

its got to do with the PH. Can't remember ATM. the Fe2O3 might work in low PH 5 - 6 soils, but i'm certain it won't work in an AP system. the trick is that if is in suspension ie not dissolved then its not available.

There are differnt chelation agents for differnt target ph's

sound right nj?

Yes, and some chelating agents are toxic to some things. The bog standard chelating agent is EDTA (IIRC)
http://en.wikipedia.org/wiki/EDTA

I wonder if rust + citric acid will form a chelate. I've mixed some citric acid and red cement colouring iron oxide in a test wineglass and I'll see whether anything happens over the next few days (iron oxide has very slow solubility, so even if the reaction is very favourable, it will take a long time to happen.

Cool, i wasn't a mad man!

I tried the exact same thing! left it for 24 hours but didn't notice any appreciable reduction in the rust. Its supposed to work though.

I was a little half assed about it really, i should have obtained a iron test kit and taken some measurements.

Once again from what i've read it SHOULD chelate the rust to an iron citerate. citric acid is easily obtainable from the supermarket and rust........

Perhaps a more soluble iron salt would work. The only one I know of is FeCl3, ferric chloride, but that's corrosive and toxic. FeSO4 is probably fairly soluble, so maybe H2SO4 + nail, then when the pH settles add ctric acid.