# Weekly, Daily Ferts, what's the difference?



## BarryH (19 Mar 2017)

The more I read about fertilisers, the more confused I become. Can anyone please advise what is the difference is dosing daily, as opposed to dosing the same, but larger amount weekly?

I was looking at different fertilisers advertised on websites and couldn't really understand why some are dosed daily, some (EI) dosed every other day, and yet more dosed on a weekly basis.

Any advice or help would be really appreciated.


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## ian_m (19 Mar 2017)

You dose daily and alternate days as the potassium phosphate reacts with the chelated iron in the micro and precipitates out and becomes unavailable to the plants. Thus if you dumped the lot in once a week you would pretty soon be suffering from iron deficiency and to a lesser extent phosphate deficiency both leading to plants dying and associated algae blooms.

Only applys if using high lights and CO2.

If non CO2 and low light once a week dosing is fine.


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## Ed.Junior (20 Mar 2017)

Also, the iron chelates break down for several reasons: in the presence of light, pH/KH too high, etc.

Dosing weekly or daily is connected to tank's growth speed. High light tanks get daily doses because they are "running fast", while non-co2 low light tanks can have a small weekly dose because they just "strolling in the park"

Dosing daily makes sure the ferts are available, at the very least at the day they are dosed. But the big doses will force the owner to do constant water changes to eliminate all the excess of nutrients in the water. This basically the Estimative Index foundation: provide every fert and CO2 in abundance, so they are not limiting the growth, and define the tank growth speed by the amount of light. Too much light and ferts/co2 might not be enough...

There are other fertilisation systems, like PPS Pro, Diana Walstad, PMDD, but I really like EI. You should study them as well, it will give you a better understanding about it.

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## Vandal Gardener (20 Mar 2017)

Good thread Barry,

My knowledge/understanding is limited to say the least but following on from Ian's post about dosing alternate days and how there's a reaction between potassium phosphate and chelated iron can I ask why it doesn't happen when dosing PMDD style?  Just to reinforce I'm not scientifically minded so will probably take me about a month to read and re read any real science answers.  The reason I ask is I use Tom Barr's PMDD with PO4 method since dealing with cups and teaspoons for measuring doesn't sit well with me.


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## BarryH (20 Mar 2017)

Thanks for the great replies everyone. Really appreciated. So, if I've got it right, the biggest difference in the use of fetilisers depends mainly of if you're Hi or Low Tech and the same with lighting?


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## ian_m (20 Mar 2017)

BarryH said:


> So, if I've got it right, the biggest difference in the use of fetilisers depends mainly of if you're Hi or Low Tech and the same with lighting?


Correct. If low light, the plants will consume less CO2 (carbon), less nutrients and produce less organic waste. The presence of high levels of organic waste cause algae and is not appreciated by fish.

So with lower light levels you can dose fertiliser less often, rely on fish poo & old fish food as carbon and fertiliser source, as well doing less frequent water changes (to remove organics and unused fertiliser), as the organic waste has time to rot away/be filtered away naturally.

Also with low tech, things go wrong more slowly eg algae appearing over weeks rather than a couple of days (or less) in high tech.



Vandal Gardener said:


> My knowledge/understanding is limited to say the least but following on from Ian's post about dosing alternate days and how there's a reaction between potassium phosphate and chelated iron can I ask why it doesn't happen when dosing PMDD style?


It doesn't happen with original PMDD as there was no phosphate in the mix, therefore chelated (iron) and other chelates stayed chelated in the bottle and in the tank.

With PMDD modified with PO4, which you refer to, you must dose macros and micros on alternate days. It is the addition of potassium phosphate to PMDD formula that makes alternate dosing being required.


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## BarryH (20 Mar 2017)

Thanks for the reply Ian. I'm starting to get there, slowly I admit but I am getting there.


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## Ed.Junior (20 Mar 2017)

The tricky one IME is Iron. This is the reason why we have so many chelators, with different properties. I think using a blend of chelators is a good thing. I tried gluconate and EDTA for a while, but my water is too hard for that, and now I am tending to EDTA/DTPA. 

If you are a subscriber of BarrReport.com, I would suggest that you go through the reports about ferts (N, P, K and Fe).

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## Vandal Gardener (20 Mar 2017)

Thanks also for answers folks and patience (Barry H) as feel like I've hijacked your thread. 

I'm a bit scared to ask/raise as more than likely I won't understand the answer, but the pmdd + po4 method taken from Tom Barr's site is actually daily dosing of both.

http://www.barrreport.com/forum/bar...more-accuracy-want-daily-pmdd-style-ei-dosing

Maybe it's just going from zero dosing to some is what I'm seeing but it seems to be working.

All the best


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## Chrispowell (20 Mar 2017)

Great thread, without going off course - how does my 'all in one' co2 supermarket feet mix deliver ion? 

Also, I dose flourish excel alongside this 'all in one' mix, am I wasting my time?


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## BarryH (20 Mar 2017)

Vandal Gardener said:


> Thanks also for answers folks and patience (Barry H) as feel like I've hijacked your thread.
> All the best



No problems Vandal, hopefully I can read the replies and learn from them.


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## Soilwork (20 Mar 2017)

Just to make matters more confusing you can dose EI daily too .  This is what i do anyway. 

I also keep iron restricted to the substrate using clay and soils.  This will provide a concentrated source of the essential trace or micro nutrients leaving me to focus on the macros.


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## ian_m (20 Mar 2017)

Chrispowell said:


> how does my 'all in one' co2 supermarket feet mix deliver ion?


It keeps the iron chelated in the bottle by keeping the solution acidic, thus preventing it reacting with the phosphate. In the tank it will unchelate due to a lowering pH and light, but hopefully the phosphate will be diluted and the amount that reacts will be minimal.


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## Ed.Junior (20 Mar 2017)

Chrispowell said:


> Great thread, without going off course - how does my 'all in one' co2 supermarket feet mix deliver ion?
> 
> Also, I dose flourish excel alongside this 'all in one' mix, am I wasting my time?


Chelators will be preserved under the right conditions, most cases by keeping the solution out of light reach and stable/acidic (e.g. ascorbic acid, vinegar potassium sorbate, etc).

Using excel in a solution will preserve the solution further. Glutaraldehyde is a sterilisation chemical (e.g. Metricide). One point to consider though is that many manufacturers already confirmed that when Glutaraldehyde is either exposed to air for some time and/or diluted below 1%, it will eventually breakdown. Different concentrations will give different results, but studies have shown that the average life of dosed Glutaraldehyde is around 10h or less.

Most chelates are sold with information about its pH effective range, like EDTA (~pH 7), DTPA (~ pH 8) and EDDHA (~ pH 10). Other chelators have different characteristics: Iron Gluconate is a much weaker chelator that requires low pH and hardness, but allows plants to acquire Iron with much less effort; Fe-HEDTA is used under pH 7 in phosphate-rich water.

In many cases, these chelators will be broken by the pH shift in the tank, specifically a higher pH, as many people use the wrong chelate for their systems. I will not afirm that no interactions between phosphates and iron happens on a tank, but one must understand that the differences in concentration between a 500ml bottle and a 100l tank are quite big.

Nonetheless, dosing in alternate days is a good thing, if people keep it steady. The point is making the ferts available, and balanced against CO2 and light

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## ian_m (20 Mar 2017)

Ed.Junior said:


> Using excel in a solution will preserve the solution further. Glutaraldehyde is a sterilisation chemical (e.g. Metricide). One point to consider though is that many manufacturers already confirmed that when Glutaraldehyde is either exposed to air for some time and/or diluted below 1%, it will eventually breakdown. Different concentrations will give different results, but studies have shown that the average life of dosed Glutaraldehyde is around 10h or less.


I think years ago, can't remember here or elsewhere, someone did experiments to make a ferts solution of macro salts, micros and acidifier and Excel or gluteraldehyde as an all one including liquid carbon fertilisation solution. I think they found that when the gluteraldehyde was diluted to give an acceptable dose with the macros/micros, it either reacted with something or decomposed. Not to sure any definitive conclusion was reached, other then better to dose liquid carbon separately from micros/macro.


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## Daveslaney (20 Mar 2017)

I think dilution once the ferts are in the tank must be a big part in this?
Because even dosing macro and micro on seperate days there will still be iron and phosphate left from the previous days doses in the tank water.
If the binding still happens it would become iron phosphate making both nutrients unavailable to the plants?


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## Ed.Junior (20 Mar 2017)

Daveslaney said:


> I think dilution once the ferts are in the tank must be a big part in this?
> Because even dosing macro and micro on seperate days there will still be iron and phosphate left from the previous days doses in the tank water.
> If the binding still happens it would become iron phosphate making both nutrients unavailable to the plants?



I do not buy the talk about "all iron gets precipitated". And I dose 10ppm of PO4 weekly, so around 13 with accumulation. I know these cheap tests we use are not reliable, but if, after checking them against known solutions, I can still find traces of the 2 days old Fe, than it most definitely was still available.

Again, you gotta know your ferts, chelators, etc. At some point I will send my water to the lab, but that can wait. 

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## Daveslaney (20 Mar 2017)

Thanks Ed.
These are my thoughts too.


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## Robert H. Tavera (20 Mar 2017)

When you fertilize daily you keep a more stable dosis, with small spikes, so the amounts of nutrients are always the ones plants need but there're not leftovers for algae. If you dose weekly you produce a huge spike in the nutrients levels, but plants doesn't use more nutrients, in this case algae can proliferate.   

This is another reason why daily dosage is so popular between advanced aquascapers. But all the chemistry related reasons said before are correct too. 

I fertilize on a daily basis, with good results. 




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## Ed.Junior (20 Mar 2017)

Robert H. Tavera said:


> When you fertilize daily you keep a more stable dosis, with small spikes, so the amounts of nutrients are always the ones plants need but there're not leftovers for algae. If you dose weekly you produce a huge spike in the nutrients levels, but plants doesn't use more nutrients, in this case algae can proliferate.
> 
> This is another reason why daily dosage is so popular between advanced aquascapers. But all the chemistry related reasons said before are correct too.
> 
> ...



Two things got my attention:

First, plants do have an optimal range for nutrients. So underdosing or overdosing ***outside of this range*** is not a good thing. But this range is quite wide. I mean, IME, 10 to 100ppm of nitrates for plants is fair game. Also, by the end of the week, with accumulation, the fert concentration is quite high. 10ppm + of PO4.

Second, I have never seen excess nutrients (except ammonia) cause algae. Excess organics, ammonia do cause issues. 

And to make it clear, plants and algae do not compete for nutrients. Light is a much better candidate. But algae can handle much worse scenarios than plants.

What remains a constant observation is that when plants thrive, algae does not 

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## Delapool (21 Mar 2017)

I've found some fish do better with daily dosing as well. This might be as I would tend to do a water change and then load up back up the ferts. 


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## Soilwork (21 Mar 2017)

When we talk about wide margins, overdosing and pump failures we are only ever addressing the macro nutrients which may well be less critical.  We never talk about the micros.

Excessive nutrients do not cause algae directly but **in certain situations** they can damage plants which in turn leads to algae.

Generalisation is a killer in this hobby and what one can do in one tank doesn't necessarily mean it can be transferred automatically to another.


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## Ed.Junior (21 Mar 2017)

The wide ranges for plants are not limited to macros. Micros can be present in wide ranges as well, but in much smaller concentrations.

If 5ppm of iron would be toxic, it should be very easy to see. Just dose and see. That is not my experience, we do not need Iron in those concentrations, but I have not observed that, on the contrary, I have seen plants thriving in it. A couple studies are also available.

For the other traces it is much more delicate. Mn and Cu, for instance. Mn has its relationship with Iron, and Cu, well, plenty of issues when that reaches even 0.5 ppm

Of course, some plants, specially in the Lythraceae family, have a narrower margin. But they also stunt for several reasons. 

If pinkish water is not an issue, you can add a lot of iron 

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## Soilwork (21 Mar 2017)

Micro nutrient toxicity will be dependent on many other parameters not just the concentration.  There are probably certain situations 5ppm iron is ok and others where it may not be for example, micro toxicity is much less of a problem in harder water and people in such regions might 'need' to dose a little more liberally than other to see a difference or address a deficiency. 

I don't dose micros.  I put them at the roots and let the plants get on with it.  A 40 litre water change will give me 0.5mg of iron and more than enough of the other traces too when used with the soil.  This is with strong light and lots of plants.  My water is very soft though (40ppm TDS) and contains very little nitrogen, phosphorus, potassium, calcium, magnesium etc so I have to add those back in.


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## BarryH (21 Mar 2017)

Some really interesting posts, thank you.

Back down at my level, I guess knowing what's coming out of my tap would be a good starting point, how do I find out what water I'm getting, I'm with Severn Trent in the Derbyshire area? The only testing kit I have is for the water in my tanks, Ammonia, Nitrite and Nitrates. Although there is also something in the API Test Kit for checking pH.


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## Daveslaney (21 Mar 2017)

If you go on severn trent website, click on the water quality link, put in your post code it gives you a basic water quality report things like GH nitrate mg/l etc in your water supply.


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## BarryH (21 Mar 2017)

Thanks for that Dave, it's frightening to see what's in the tapwater we drink.

Some of the names on the download I've never even heard of. Of all of the "ingredients" shown, Iron seems to stand out as a much larger percentage figure than any of the others listed.


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## Soilwork (21 Mar 2017)

BarryH said:


> Back down at my level, I guess knowing what's coming out of my tap would be a good starting point,



This is fundamental in my opinion.  Not necessarily for growing plants but to help with troubleshooting and understanding in the event something does go wrong.

How much iron do you have?


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## Daveslaney (21 Mar 2017)

BarryH said:


> Thanks for that Dave, it's frightening to see what's in the tapwater we drink.
> 
> Some of the names on the download I've never even heard of. Of all of the "ingredients" shown, Iron seems to stand out as a much larger percentage figure than any of the others listed.


The figure for iron will be in ugl thats parts per billion.
Most of the others will be ppm.


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## Daveslaney (22 Mar 2017)

What about Ferrous Gluconate iron, As used in flourish iron.
Is there less likely to be a reaction caused using this?.


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## Ed.Junior (22 Mar 2017)

Soilwork said:


> micro toxicity is much less of a problem in harder water and people in such regions might 'need' to dose a little more liberally than other to see a difference or address a deficiency.



Ok, let me be honest: outside of crazy situations (e.g. dropped a bottle of micros into the tank), I currently do not believe in micro toxicities in our tanks. I heard a lot about it, without substantial evidence.

But I am always open to learn new things 

With this in mind, I would like to ask: what is the relationship between iron/traces and hard water? I am curious to know where this is coming from. 

Besides the interactions between chelators and pH/KH, or the influences of higher levels of PO4 on hardness, I never heard anything similar.

Sincerely curious 


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## Ed.Junior (22 Mar 2017)

Daveslaney said:


> What about Ferrous Gluconate iron, As used in flourish iron.
> Is there less likely to be a reaction caused using this?.



Fe Gluconate is great, it provides iron at a low acquisition cost for the plants, but I am afraid that lots of people are just wasting it at high kH. The bond is so weak that it will break down in hours, not days. 

People with higher kH will definitely enjoy better results with EDTA/DTPA.
That being said, there is no "damage" dosing it daily on said aquariums, as long you are only dosing Fe Gluconate. I have no idea what is inside of a Flourish Iron bottle.

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## ian_m (22 Mar 2017)

Ed.Junior said:


> With this in mind, I would like to ask: what is the relationship between iron/traces and hard water? I am curious to know where this is coming from


Generally hard water is a higher pH ie alkaline and this cause the chelate to unchelate and release the iron, which may or may not stay in solution and be available to plants.

This is why some people say "I have hard water and have switched to xxxx type chelated iron" because it is more stable at higher pH.

Below is the standard graph everyone refers to. So the more expensive Fe DPTA and Fe EDDHA stay chelated in higher pH, that standard Fe EDTA


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## Ed.Junior (22 Mar 2017)

ian_m said:


> Generally hard water is a higher pH ie alkaline and this cause the chelate to unchelate and release the iron, which may or may not stay in solution and be available to plants.
> 
> This is why some people say "I have hard water and have switched to xxxx type chelated iron" because it is more stable at higher pH.
> 
> ...


Thanks for the answer Ian, but is not my question 

As I already mentioned, I am fully aware of the interactions of the chelators themselves, as I already failed in the past when trying to dose Iron. Lesson learned. Important to notice that some bonds are sensitive to kH, but since high pH and kH usually walk hand in hand, thats fine.

I was specifically reffering to Iron/Traces, and not to the chelators. Soilwork mentioned that traces might not be available in hard water, and I got curious, specially about the traces. Since PO4 in high concentrations also interferes with hardness, I thought that maybe he was reffering to something I wasnt aware of.



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## Daveslaney (22 Mar 2017)

Thanks Ed.
Florish iron uses Ferrous Gluconate for the iron.
No chelators.


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## Soilwork (22 Mar 2017)

Availability and toxicity are very different things.  Availability yes I was referring to iron.  Toxicity I was referring to low water hardness providing less protection against heavy metal toxicity in aquatic organisms.

Do I really have to provide links? Water hardness and metal toxicity is pretty well documented

Water hardness, pH, temperature, presence of humic substances.

I don't know what the toxicity levels are for the type of organisms we keep and that is precisely why I am more careful.

Issues were apparently arising for some when targeting a specific iron concentration using dry micro mixes as the concentration of the other metals was increasing to with each EI dose.

http://www.tandfonline.com/doi/pdf/10.3184/095422911X13201685540769

I don't really want to get to involved in this again.  My point was to explain that there are many ways to grow aquatic plants successfully and that even the results of identical practices can differ dramatically depending on where we get our water from


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## Ed.Junior (22 Mar 2017)

Chill, all good 

The way you spoke I thought you were pointing at something new related to traces. Also, I am speaking only about plants, big difference. 

We do disagree on some stuff, but who doesn't, come on 

Anyways, thanks for the reply.

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## Soilwork (23 Mar 2017)

I'm good.  I've lost shrimp and fish when dosing large amounts of dry traces in to my soft water tanks.  I've had stunted plants and chlorosis, necrosis etc.  At least three times i can remember that adding trace mixes in large quantities has caused problems.

I find it strange also that the Rotala butterfly calculator has (recently?) lowered its target dose of iron for EI using dry trace mixes from 0.5ppm to 0.2ppm and that GLA has altered its micro mix for PPS pro by a whole order of magnitude.  (See in red)

http://blog.greenleafaquariums.com/2013/02/28/our-new-pps-pro-fertilizer-pack-just-mix-dose/

Happy plant keeping


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## Ed.Junior (23 Mar 2017)

GLA sells the salts but they are not responsible for PPS Pro. For Rotala, I will ask Fablau and Jason about this

Although Tom mentioned some values in his initial/famous post about EI, he never focused on the values, but rather on the method. "How much" is always an adaption.

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## Soilwork (24 Mar 2017)

I agree.  I understand the relationship between PPS pro and GLA too but still seems odd the levels have been dropped significantly.  Thanks, it would be interesting to find out why the change was made.


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## Ed.Junior (24 Mar 2017)

Will do. I guess they are just giving in to pressure. Always easier/less responsibility as a manufacturer/seller to aim lower. They provided afaik no studies to support this change  

My concern is more about the belief that lots of traces are always bad. If you dose a lot and have success, then undoubtedly iron/traces were not available, but instead precipitated, etc. This is nonsense.

I do know serious people having great success with minimal traces, and they also say that too much traces were not beneficial to them. I have no issues with this. Check Burr740 journal for instance.

But this does not prove that "lots" of traces are bad. Some species, even some families (e.g. Lythraceae) are known to be picky about this, and do have a narrower optimal range. On the other hand we have a ton of studies displaying how hidrylla verticillata and egeria densa are used to clean contaminated lakes, by removing all the heavy metals. 5ppm of iron cleaned in days, and the dry matter exceeds 80ppm of iron. Same for copper, zinc, aluminium, manganese, etc

So, from my perspective it is very complicated to discuss toxicities in a tank. People think that chlorosis signs relates only to iron deficiency, when again and again studies show that the same signs can be induced by something else, as seen in very highly contaminated waters. So the whole borders of toxicity/deficiency is far from clear.

Maybe if people double on EI, skip water changes, then yes. But one must ask: dude, what are you doing?

TL;DR: You can have success with a lot or little traces. Those who dose a lot dont necessarily "lose" the traces to precipitation/etc. They might be there, and results are great also.


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## Soilwork (24 Mar 2017)

Of course plant nutrition is complicated.  Lots of traces I don't have a problem with too much is different. 

Perhaps it was pressure or the overwhelming number of cases found in threads like these?

http://www.plantedtank.net/forums/1...ers/503585-toxicity-csm-b.html#/topics/503585

http://www.barrreport.com/forum/barr-report/estimative-index/14637-how-easily-csm-b-can-become-toxic

http://www.plantedtank.net/forums/1...csm-b-toxicity-experiment.html#/topics/853001

In one of those threads it was determined that Tom was using a very conservative EI when it came to traces.  Iron was dosed liberally and was probably required.  Also note that they were talking about the percentages of nutrients found specifically in CSM+B.

Could you also imagine how much money GLA would lose now that the micro mix is ultimately going to last 10x as long? If I were them I would want to end this talk of micro toxicity unless there was some cause for concern. 

I think this is the wrong time and place to discuss this and I'm aware we are perhaps derailing this thread somewhat so I'm going to bow out here. 

I'm one of those people that doesn't dose micros at all.


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