Backyard Aquaponics
A place to discuss aquaponics

Janet I have absolutely no doubt that you will succeed which ever way you go.... and I suspect even if it may mean some disappointment in terms of results, you'll keep trying new things to find out what works and what doesn't anyway....

Hat's off to ya.... I likes ya girl

Thanks, Rupe! :blush:

btw, I checked the ingredients on my fish pellets. The first 4 ingredients are all grain meals, then fish meal, then feather meal. (Ith leavth a fuffy tafte on the palate.)

Feather meal....ground up chickens?

bleah.

Janet, it may be a bit late, but not enough iron uptake or apparant iron deficiency can also come from:
- Copper / zinc deficiency
- Calcium / manganese / molybdenum / phosphorus / zinc excess
(http://www.totalsoil.com/TSM/mission/showmeexcess.htm, http://www.advancednutrients.com/articl ... ticleID=41)

I remember you used to use calcium hydroxide and a lot of calcium carbonate to keep your pH up - maybe an excess of calcium caused some of your plants to have trouble with iron uptake? I'm just guessing - maybe somebody else can look into this more.

I am quite certain that my iron def is caused by excess calcium or the high pH of my system. I've taken to spraying the foliage of the plants with Iron sulfate mixed with water to take care of the problem. This is probably easier on the system/fish/bank account since fish do better with their metals provided in their diet rather than in their environment and adding lots of iron that precipitates out is hard on the system and costly in chelated iron. The Iron sulfate (which would not be appropriate to be dumping large amounts directly into the system) is much cheaper and is effective as a foliar spray. Beware though that it does stain surfaces though.

Janet, how has your system been doing lately on the deficiency front?

What IS your PH atm, TCL?

i wouldn't expect foliar feeding to help if it was an excess of another minearl

I haven't seen a pH below 7.6 since I started using shells as part of the media mix.
The pH of the big system hovers between 7.6 and 7.9 when I add top up water.

The foliar feeding has made a huge difference to most of the plants.

Holy Hydroxide, Batman!

Re: first post in thread

My first thoughts are: a)how much iron chelate are you adding, b) to what volume of water and c)how often. 2ppm every 2 weeks is what I use (2g/1000L). I think this is the consensus?

Iron sulphate (and I believe iron chelate (Fe EDTA)) is oxidized in the presence of air, so ensure the packet is always closed- when it is fully oxidized it will turn white and in this form it cannot be taken-up by the plants. This would be my first thought as to why iron levels seem to be low if the right levels are being added.

We have a lot of chlorine in our tap water here and I use thio to neutralize. I add Fe EDTA and haven't had any problems with low iron levels. I don't think it's reacting with thio as more people would have had this problem

Fe EDTA is added to plants in alkaline soils as (from my understanding) it is not precipitated at high pH, unlike other forms of iron such as iron sulphate. EDTA is a 'chelating agent' which is used to keep chemicals in a solution in suspension. Therefore, your plants should still be able to take it up even with a pH closer to 8.

Hope this helps :

Zero problems with flowerdrop here. I am not adding anything at all?

I have Tomato's, Broccoli, Cucumbers, Eggplant, Strawberries, Basil, Brussels Sprouts, Dill, Anaheim Peppers, Jalapenos, Bird Peppers, Habaneros etc etc.

Maybe it is the water? Ours is very low chlorine added to the point it degases in about 20 mins according to the water department. So much so that I can add direct water to the tank and never have problems with bacteria death. That must mean the chlorine is low enough to not cause any problems?

If you want pictures I can supply but I have fruit set all over the place..

High soil or water PH disrupts iron uptake,, add iron till the cows come home and you'll still have the problem. Foliar spraying adds iron to the leaves ( a temperary solution).
Most plants like PH around 6 -6.5,....., may I suggest a compromise 6.5 - 7.
At 6.5 the iron and other nutrients become more available for uptake by the plants.

The challenge is keeping the pH at that level - ie not letting it drop significantly lower and not raising it to 7.5 or thereabouts through CaCO3 saturation. While we have shown that nitrosomonos and nitrobacter will continue to function at pH well below 6, I think that where stocking density is high (based on biofiltration capacity) then this is going to present problems.

I guess that once the system is stable, it is conceivable that one could work out what the pH drop is per ?? grams of feeding and how much CaCO3 needs to be added weekly (or more frequently) to keep the pH relatively stable at pH 6.5 or thereabouts. It is just a shame that we don't know of something that will buffer the system at 6.5.

Different buffering agents try to stabilise at different PH's,,,
Here's a basic list ,, I've not had time to see if any are fish-plant safe.
http://en.wikipedia.org/wiki/Buffer_solution

Alternatively ,, have a bag of buffer ,, that can lowered or raised to compensate for the PH wanted,,???