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Hello, again, Another question if I may.

My system has been cycling (fishless) for about three weeks, and doing very well. It is pulliing my ammonia levels down well, nitrates are low, and nitrates at about 50 (need more plant load).  But I keep adding chelated iron almost daily to get the level up to about 0.5, and the next day it is usually down to 0.2 and in twos days almost gone. Is there something missing? or could there be an "iron-eater" in my system (yikes!)).

 

Thanks

Dan

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Thats crazy, what's your pH? What plants do you have in there? No need for more plants at 50ppm nitrate, wait till it starts to get above 100 if you want faster production

My PH is running right around 6.9 - 7.0.   It has climbed today to 7.3, the temp here today has dropped to unseasonbly cool - around 50 degrees I don't know if that would affect the PH?.  I have tomatos and strawberries, and yes - I am not concerned about plant load, and I may go pee-ponics for a while with just a few large goldfish - just because I don't want the hassle of fish right now.

 

Thanks

Dan

Are your plants showing symptoms of iron deficiency?  If they are, then you keep adding the chelated Iron.  If the plants are looking good and green and no sign of the yellow leaf between the green veins then you are fine.

Let the plants talk to you.  The new leaves show Iron deficiency first and keep watching the new leaves for signs of recovery. 

 

If the plants are in really bad shape, mix up a foliar spray with iron and carefully give them a spritz on a cool day (some iron sprays will stain so why I say carefully)  Mix according to directions for foliar application since strong foliar sprays can burn plants.

 

In Pee Ponics, potassium and iron are both the most likely deficient things as well so some seaweed extract and chelated iron on hand can be helpful.

Yes - the plants are iron deficient - I'm just wondering if I will need to be adding iron constantly, or if the system will straighten out eventually.  Is there some condition that causes iron to drop out?

 

Thanks

Dan

TCLynx said:

Are your plants showing symptoms of iron deficiency?  If they are, then you keep adding the chelated Iron.  If the plants are looking good and green and no sign of the yellow leaf between the green veins then you are fine.

Let the plants talk to you.  The new leaves show Iron deficiency first and keep watching the new leaves for signs of recovery. 

 

If the plants are in really bad shape, mix up a foliar spray with iron and carefully give them a spritz on a cool day (some iron sprays will stain so why I say carefully)  Mix according to directions for foliar application since strong foliar sprays can burn plants.

 

In Pee Ponics, potassium and iron are both the most likely deficient things as well so some seaweed extract and chelated iron on hand can be helpful.

Yes, pH!!!!!  What is your system pH?

 

High pH and lots of calcium can lock out Iron so the plants can't use it.

I have a system where silly me used shells as my media so my system pH can't really drop below 7.6 for very long.  That system needs regular additions of chelated iron because the high pH locks it out.

That's the part that had me confused so I didn't reply.  It seems you have an Iron test kit - and I assume it would pick up if there's iron in the water regardless of pH (?) so the question is what is it in your system causing the iron to disappear...

 

It would help if you could post pics and a list of materials you used. I'n not a chemist but maybe TC and I can figure something out, she's smarter than me

Actually, I'm not that smart when it comes to the chemistry.  I've just been doing this for a few years now and have picked up some bits and pieces from the people around who do know more about Chemistry.  Rupert of OZ has a lot of good info about the chem involved in Aquaponics as does Nate and their tips have helped me a lot.

 

Which reminds me, I should go add some Iron to my big system as it's been looking a bit sickly for a while now and I should have dosed it before I left town the last time.

 

Tip, if your pH is up at 8 or above, you may have real trouble keeping all but a few plants really happy.  My big system runs at 7.6 and I'm able to manage with many plants but if you can get the pH down closer to 7 it is much easier to make most plants happy.

I asked the guy who posted this vid (http://www.youtube.com/watch?v=CGOIL7g9zV4&feature=related) how he can run his garden at a pH of 7.0 without any problems and I believe he said (his english is terrible) that it's the biodiversity that grows with age that allows plants to absorb nutrients at a broader range than usual. makes sense to me because I once read that bacteria all responsible for most if not all of nutrient absorption by plants

 

In a new system you will probably have trouble if your pH isn't below 7

Yep, And new systems often start out with hard tap water (like up over 8) and they struggle for a while till they really get established. 

In a new system it hasn't had time to build up a supply of trace elements (which is why most new systems does with seaweed extract a bit during the first season.)  The trace stuff is slower to break down from solid form into something useful for the plants.  Worms and heteratrophic bacteria take care of this but it takes some time to really get established.  I have definitely noticed that things do get better with time in aquaponics.

 

Once a system gets balanced and settles in.  A pH anywhere between 6.5-7.6 can be acceptable, just learn what works in your location (source water does play a big part in how things balance out and what supplements might be needed like iron or different things for buffering the water's pH from dropping too low and so on.)

Thanks Guys,

 

My PH is staying around 7.0 - so it is very good, and yes the question really was - why is the iron simply going away?  And you have ansewered that one as well.  I think I can relax knowing that eventually the system will start producing more iron & trace elements on it's own.

 

Thanks again

Dan

TCLynx said:

Yep, And new systems often start out with hard tap water (like up over 8) and they struggle for a while till they really get established. 

In a new system it hasn't had time to build up a supply of trace elements (which is why most new systems does with seaweed extract a bit during the first season.)  The trace stuff is slower to break down from solid form into something useful for the plants.  Worms and heteratrophic bacteria take care of this but it takes some time to really get established.  I have definitely noticed that things do get better with time in aquaponics.

 

Once a system gets balanced and settles in.  A pH anywhere between 6.5-7.6 can be acceptable, just learn what works in your location (source water does play a big part in how things balance out and what supplements might be needed like iron or different things for buffering the water's pH from dropping too low and so on.)

The fish food you are using will play a big role in how much supplementing you might have to do as will your water.

Now if your plants are suffering greatly from Iron deficiency, that may explain why you add iron and check the levels and then the next day there seems to be less.  Your plants may be using it that fast to catch up so once they do catch up things may settle down a bit.

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