trace mix

[johnson529]

After reading clives tutorial on dosing EI dry ferts I decided to give it a bash as TPN+ was costing a fortune and must say its been very easy to do and its going to save me loads in the long run. I was just using the dosing calculator on the planted tank site to see what my ppm dosing is and thought I'd look more into depth at my trace mix.

I bought a 200g batch and it consists of:

2.40% iron
0.70% Manganese
0.20% zinc
0.16% copper
0.20% boron
0.004% cobalt
15.00% Magnesia

I mix half a teaspoon of this into 200ml of water and dose 25ml mondays wednesday and friday.

Compared to breakdowns of other trace mixes I've seen, my content, especially iron, seems to be a little on the low side. Can anyone else confirm this and if so what action should I take? More trace mix per 200ml or buy extra fe and add it to the batches I make up?

Thanks

 

[ceg4048]

Hi mate,
You need to just relax let your plants tell you what to do. The iron content is a proxy for the other metals, though I'm not sure why the Mg content is so high. It's almost as if someone added trace mix to some Epsom Salts and called it good. In any case, just dose per the tutorial and look for Fe deficiency. This will show up as yellowing of young or new leaves. If that doesn't happen then you have a good mixture and you will avoid wasting it. If you do see deficiency then just double the dosage and call it good. There is no point in buying yet another product when you already have it in the mix.

Trace mix is the least of your worries in terms of what plants need, yet it's often the most expensive of the dry powders, so I avoid wasting it as much as I can.

Cheers,

 

[johnson529]

the new leaves coming through are green and good but some of the older ones are turning slighly yellow. Does this count as iron defieciency?

 

[ceg4048]

No.
Buckle your seatbelt Dorothy, cause Kansas......is goin' bye-bye...

In aquatic plants, enzymes and proteins are produced in order to combine with specific nutrient molecules, and to move the nutrients from place to place within the plants distribution network. This behaviour is called "Translocation".

Nitrogen, Phosphorous and Potassium (NPK), being in much greater demand (and being much more important) than any of the micronutrients, translocate very easily. So when a new leaf is being formed, NPK being very mobile, can move quickly from an old leaf to the new leaf site to support the growth and development of the new growth. So study your plant very carefully. When you see that new growth comes in looking nice, but old leaves are discoloured, this tells you that mobile NPK is being translocated to the new growth site due to an NPK shortage.

Chlorophyll is green and is made up primarily of Nitrogen, so if an old leaf turns yellow this means Nitrogen is being pulled out of the old leaf and being sent to the new leaf. That means you have an N shortage.

Micronutrients are much less mobile in plants. Look at your list for a second. Can you see that they are mostly highly reactive metals? Their high reactivity is precisely why they are being used, but is precisely what makes them so toxic. That's why the plant only wants to deal with numbers like 0.004 % Cobalt. As a general policy therefore the plant tends to distribute micronutrients only on initial uptake and then to leave them be.

Of these metals, Iron and Magnesium are slightly more mobile, but not nearly as mobile as NPK so if you have an Fe/Mg shortage then the old leaves will tend to stay green while the new leaves will come in yellow. Chlorophyll is about 3% by weight Magnesium. Iron is used in the photosynthesis chain to move electrons.

We can surmise therefore that due to low mobility, micronutrient deficiencies will typically affect young leaves FIRST.
If not corrected, long term, the plant as a whole will slowly decline and will suffer reduced growth rate and other symptoms.
This is one of the reasons why tap water is so much better for plants generally, than RO/DI water. It's generally loaded with micronutrient metals - of course this is often at odds with fish requirements.

Hope this makes sense. 8)

Cheers,

 

[johnson529]

Ha ha Loving the matrix quote. Was only watching it the other night too. I've noticed you use quite a few in other posts as well.

Yes mate, what you just posted makes a lot of sense. I can honestly say I've learnt more on plant biology in the year I've been registered on this site, than I did in my entire school period.

I'll be keeping a close eye on these slighly yellowing leaves and upping my KN03 a little if it continues.

cheers for your help dude