Phosphate and zinc levels

[plantmaster]

For some time now i have notice my plants stunting , small leaves, yellowing and some melting on new growth , i have notice this especially after adding higher phosphate levels.....anyhow after doing some reading on net as you do i seen alot of sites saying that high phosphate levels can lock up zinc!!! after reading this i up the traces (flourish comp) but with no improvement. I then brought some zince sulphate heptahydrate and added .5 gram to my 90 gallon and there was a explosion of growth on my rotala, pearling everywhere and plants greening up.

Could i have a bad batch of traces (flourish) that contains no zinc? or do we need higher zinc levels with high phosphate levels.

 

[yme]

did you add a chelator as well? I thought Zn should be chelated.

greets,

yme

ps: don't know the answer

 

[plantmaster]

its zinc sulphate heptahydrate 98% pure 21.5 %zinc and 10% (s)
thats all i know

 

[Tom Barr]

Who claims that high PO4 locks up Zn in aquatic plants?

I think it's due to more growth in your results.
If you are limited by one nutrient, say PO4, adding say 2-3ppm will switch the most limiting factor to something else. This has NOTHING to do with binding of anyone nutrient with another.

It has to do with Liebig's Law of the Minimum.
If the focus is on all the nutrients and providing non limiting ppm's/amounts, then you do not chase one low nutrient level to the next.

This "chase effect" causes many myths in aquariums.

Many added PO4 and end up with algae, many did not. So we know it must be some other cause than PO4. If you add lower CO2, but have a system that is more strongly limited by PO4 than say CO2, adding PO4 will dramatically increase the rates of growth, then the demand for CO2 will go up dramatically.

So now you are CO2 limited, whereas prior, the limitation was PO4. Indirectly, ou provided stable low CO2 to the plants by strong PO4 limitation. PO4 was much more a bottle neck than CO2.

When you test PO4 independent of CO2, or Zn or which ever other nutrient you chose, now we see that there is no effect.

This means that Zn or the CO2 in the above example was not independent, so you cannot say say PO4 additions cause algae, nor that PO4 binds Zn, that's not been demonstrated not matter how hard the folks on line want to yell and shout.

Here's how you know:
I add plenty of PO4 and Zn, much like you did.
If it was due to binding as the myth/claims state, then adding more Zn/PO4 would increase the binding effects, more concentration.

At least that's what we might expect.

I have no issues with my plants at 5-10ppm of PO4. No issues with Zn either.
I add a fair amount of each.

I'd stick with your plan, you might consider tweaking the CO2 a bit when you add PO4 and add more traces in general, least you fine another trace metal you might be lacking later.

More light= more CO2= more nutrients.

Stick with that.

If you want less nutrients/growth etc, use less light= less CO2 = less nutrients.
Fairly simple idea and common sense.

Regards,
Tom Barr

 

[yme]

Let's put the question in another way:

Is it possible to be Zn limited when you dose EI trace elements...

(because that IS the question )

I don't have any data on it. but I would say: no.

I would suggest that you stop the Zn addition, do a 2 times 50% water exchange, and see what happens...
If you do see stunting etc again: add Zn.
If you were Zn limited, the plants should grow again.
repeat this 3 times.

Only then can you semi-scientific conclude that you were Zn limited.

Are you willing to do this?? If not, then it is just an observation, without validation. ergo: doesn't mean anything.

btw: It is nice to torture your tank

greets,

yme

 

[Tom Barr]

Let's put the question in another way:

Is it possible to be Zn limited when you dose EI trace elements...

(because that IS the question )

I don't have any data on it. but I would say: no.

Not if you are using CMS or Tropica master grow at the suggested levels.
Flourish?
Well let's take a look at Zn % in each of those 3 brands.......
See below.

EI and most hydroponic solutions, eg hoaglands' etc are non limiting for Macro nutrients, but trace brands often vary in the hobby and the % of heavy metals.

Modified Hoaglands' is about 5X richer than EI's general targets, but roughly the same. If it applies to EI, then it should also apply fairly well to Hoagland's.

Now if someone uses some form of trace that does not include Zn, or is rather low, then sure, but then that's the user's issue doing that, not something inherent with in EI's suggestions.

I would suggest that you stop the Zn addition, do a 2 times 50% water exchange, and see what happens...
If you do see stunting etc again: add Zn.
If you were Zn limited, the plants should grow again.
repeat this 3 times.

Only then can you semi-scientific conclude that you were Zn limited.

Yes, Flouish has been used for a long time, it is rather lean though in Copper and Zn.

See here compared to CMS and Tropica:

Fertilizer Comparison Chart, by Giancarlo Podio

A few orders of magnitude difference.
Seems like a possible factor to me. I have used it but always liked richer brands and Tropica (which was used for EI, not flourish).
The difference are apparent to me, somewhat subtle to others.

I use a modified trace that's richer than Tropica and has more Fe.

I see no issue adding Zn to flourish at the higher rates in other brands.

Regards,
Tom Barr

 

[yme]

Nice post Tom!

I never directly compared TMG with flourish. just assumed that they were more or less comparable. NOT!.... it's totally different. almost unfair to compare the 2 products if one uses x ml of traces.

greets,

yme

 

[plantmaster]

Thanks for replies Yme , Tom

Adding extra zn to flourish seems like a good idear might also need extra boron.
If only i could get my hands on some CMS+b

 

[charlie]

Thanks for replies Yme , Tom

Adding extra zn to flourish seems like a good idear might also need extra boron.
If only i could get my hands on some CMS+b

I`m thinking of doing the same, i need to source some Zinc sulphate.
How much Zinc should one add to 500 ml of Flourish?
Regards

 

[Tom Barr]

Nice post Tom!

I never directly compared TMG with flourish. just assumed that they were more or less comparable. NOT!.... it's totally different. almost unfair to compare the 2 products if one uses x ml of traces.

greets,

yme

Well, I'd always sort of compared them equally myself, but looking at the Cu/Zn and others, they are very different.

This is why I like TMG more than likely.
I think Seachem assumes that less of these metals is better, but still adds them.

Tropica focuses more on the plants.
SeaChem does not commercially grow plants of any sort, Tropica certainly does.



Regards,
Tom Barr

 

[Tom Barr]

Thanks for replies Yme , Tom

Adding extra zn to flourish seems like a good idear might also need extra boron.
If only i could get my hands on some CMS+b

You might ask Paul and others in Oz.
Dave Wilson might?

I can arrange for some to be shipped there, the dollar is weak right now, so it would be fairly reasonable.

I'd spike CMS+B with more Fe DTPA, say 1 tsp per Table spoon of the CMS+B. Oz tap seems pretty high in KH in many locations, so this should help.

Regards,
Tom Barr

 

[plantmaster]

You might ask Paul and others in Oz.
Dave Wilson might?

I can arrange for some to be shipped there, the dollar is weak right now, so it would be fairly reasonable.

I'd spike CMS+B with more Fe DTPA, say 1 tsp per Table spoon of the CMS+B. Oz tap seems pretty high in KH in many locations, so this should help.

Regards,
Tom Barr

Ive been doing some searching and it seems like the guys from aquagreen are using rexoin apn micromix , it looks very similar to CSM+b and also includes Iron DTPA 6%. I will be ordering it.

Tom im not to sure about the low kh here and using Iron DTPA , my ph gets down to low 6 , should i buy some iron EDTA and mix it in?.

Tom can you see anything wrong with using these traces for EI.

Product Specifications APN MICRO MIX

Big thanks

Graeme

 

[Tom Barr]

If it's some what close, it should work, CMS is more for typical plants, aquatics are not THAT different really, many nut cases seem to insist they are.

A plant is a plant. Aquatic have light and CO2 challenges, they can go both ways in their natural habitat for foliar and fertigation + roots, horticultural growers use both because they can and it works.

But natural terrestrial plants rarely get much from their leaves, except for a few carnivorous plants etc NATURALLY.

So this nature is best business is crazy for plants for horticulture/argiculture/crops etc/landscaping etc . So many try to sell people on that.

Regards,
Tom Barr