# Front loading vs daily dosing



## hypnogogia (8 Jun 2022)

Over in the IFC fertiliser thread (and excellent tool btw.) I asked a question  about front loading and accumulation, which I thought was worthy of further discussion/exploration.

My question was why, with front loading, one only doses for the replacement water and not the whole tank. The answer to that was to avoid accumulation.  Now, if I understand correctly, with daily EI dosing, we do regular 50% water changes to keep accumulation in check.  My question though would be, why would we be more concerned with accumulation when front loading than when daily dosing?  The accumulation that occurs would conceivably be the same amount irrespective of approach. So, the question still remains - we could dose for the whole tank and front load, do a 50% water change to keep it in check, or if we are genuinely concerned with accumulation, then perhaps we should only does for the weekly water change amount even if dosing on a daily basis.

I'd be interested in others' views and also if I've got completely the wrong end of the stick.


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## tiger15 (8 Jun 2022)

I think the daily dosing is not about accumulation, but to provide steady supply of nutrients plants prefer.  The weekly 50% WC is to reset and prevent accumulation.

I don’t dose daily except iron which has short bio available life.  I front load all other nutrients after weekly 75% WC.  I keep heavy bio load that supplement substantial N and P daily.


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## GreggZ (8 Jun 2022)

hypnogogia said:


> Over in the IFC fertiliser thread (and excellent tool btw.) I asked a question  about front loading and accumulation, which I thought was worthy of further discussion/exploration.
> 
> My question was why, with front loading, one only doses for the replacement water and not the whole tank. The answer to that was to avoid accumulation.  Now, if I understand correctly, with daily EI dosing, we do regular 50% water changes to keep accumulation in check.  My question though would be, why would we be more concerned with accumulation when front loading than when daily dosing?  The accumulation that occurs would conceivably be the same amount irrespective of approach. So, the question still remains - we could dose for the whole tank and front load, do a 50% water change to keep it in check, or if we are genuinely concerned with accumulation, then perhaps we should only does for the weekly water change amount even if dosing on a daily basis.
> 
> I'd be interested in others' views and also if I've got completely the wrong end of the stick.


Front end loading and dosing for replacement water and not the whole tank are two entirely different topics.

Contrary to what most believe people like me who front end load do it to keep nutrient levels more stable. Dosing every other day typical leads to a very low nutrient level right after a water change, and then the levels rise and peak right before the next water change.

I can use my tank as an example. My plant uptake of nutrients is just a little higher than the tank generated nutrients (fish/feeding/waste). Let's say I were to dose 12 ppm NO3 weekly and perform a 2/3 water change. If I were to dose the traditional way I would perform a water change then dose macros every other day. This is what my nutrient levels in the tank would look like. Pay attention to the daily NO3 level in week 11. Notice how the nutrient levels would start very low then rise until the end of the week. Many sensitive species hate that dip in nutrients.





Now let's take the same dosing but dose all weekly macros right after a water change. Notice the difference in the daily NO3 level in week 11.




I think you would be surprised at how many people are now using this method. Personally I started front end loading about 5 years ago or so. My main thought was that if there is an "optimum" amount of nutrients in the water column that plants prefer, then why not try to keep it there?

If anything else it sure is a lot more convenient. And even if someone does not front end load, most would benefit from dosing something like 50% of the weekly total right after a water change then two 25% doses during the week. You want to avoid that big drop of nutrients from the water change.

Now as to dosing based on the amount of water removed or the entire tank it is simply a matter of semantics. It's two ways to report the same thing. I started a crusade years ago to get people to think of "target" dosing, but old habits die hard.

The reason I think it works better is that a lot of times people try to copy someone else's dosing. But what they don't realize is that if they are not on the same water change schedule, then they are not providing the same level of nutrients in the water column. It all has to do with accumulation.

If you change less water, then your accumulation will be higher. If you change more water then your accumulation will be lower. By a lot.

There is simple formula to calculate the theoretical maximum accumulation of fertilizers. It's the weekly ppm divided by the water change percentage.

So let's take NO3. If someone is dosing 12 ppm weekly, this is how water change percentage affects accumulation.

12 ppm weekly at 25% water change is 12 ppm/0.25 = is 40 ppm max NO3 accumulation.
12 ppm weekly at 50% water change is 12 ppm/0.50 = is 24 ppm max NO3 accumulation.
12 ppm weekly at 75% water change is 12 ppm/0.75 = is 16 ppm max NO3 accumulation.

So you see 12 ppm NO3 dosing can mean a lot of things depending on the water change schedule.

If our "target" in the water column is 24 ppm, then we would report it as a 24 ppm target dose. It is exactly the same as dosing 12 ppm NO3 with 50% water change. So again it's two ways of saying exactly the same thing.

I hope that makes some sense but I am guessing you are sorry that you asked. Now I need to lie down with a cold compress on my forehead for a few minutes!


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## Hanuman (9 Jun 2022)

hypnogogia said:


> My question was why, with front loading, one only doses for the replacement water and not the whole tank. The answer to that was to avoid accumulation.


That is not exactly how I put it in the IFC calculator thread. What I said, or at least wanted to convey, is that the by-product of using your WC volume as a basis to dose is no fert accumulation, but that is NOT the aim/objective of front loading. Gregg explained it above which is consistent with the explanation I gave <here>.
Here is also a <thread> where we discussed about it. And here <a specific post> in that thread where I made a 1 week simulation to compare front load vs other dosing technics.


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## hypnogogia (9 Jun 2022)

@GreggZ thank you that is very helpful, by means of the tables you presented.  I have just one further question.  



GreggZ said:


> 12 ppm weekly at 25% water change is 20 ppm/0.25 = is 40 ppm max NO3 accumulation.
> 12 ppm weekly at 50% water change is 20 ppm/0.50 = is 24 ppm max NO3 accumulation.
> 12 ppm weekly at 75% water change is 20 ppm/0.75 = is 16 ppm max NO3 accumulation.


If it is 12pm, why is the calculation 20er/0.25?  What would it be if it is 15ppm weekly?


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## hypnogogia (9 Jun 2022)

Hanuman said:


> Gregg explained it above which is consistent with the explanation I gave <here>.


Thank you.  I'd actually missed that before I posted my thread.  From @GreggZ I can see that it is a combination of consistency and avoidance of a dip after water change. , which all makes sense now.


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## Hanuman (9 Jun 2022)

hypnogogia said:


> If it is 12pm, why is the calculation 20er/0.25?


It looks like @GreggZ  got a bit excited and finger happy. It should read:

12 ppm weekly at 25% water change is *12* ppm/0.25 = is *48* ppm max NO3 accumulation.
12 ppm weekly at 50% water change is *12* ppm/0.50 = is 24 ppm max NO3 accumulation.
12 ppm weekly at 75% water change is *12* ppm/0.75 = is 16 ppm max NO3 accumulation.



hypnogogia said:


> What would it be if it is 15ppm weekly?


15 ppm weekly at 25% water change is 15 ppm/0.25 = is 60 ppm max NO3 accumulation.
15 ppm weekly at 50% water change is 15 ppm/0.50 = is 30 ppm max NO3 accumulation.
15 ppm weekly at 75% water change is 15 ppm/0.75 = is 20 ppm max NO3 accumulation.

There is a calculator done by Zorfox that calculates accumulation. Rotala Butterfly also has an accumulation calculator.


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## ian_m (9 Jun 2022)

Of course front loading macros precludes any dosing of micros as micros, especially the iron, will react with the phosphate in the macro and precipitate out of solution and become unavailable to the plants. Also the chelates in the micro generally have a short (24 hours ?) lifetime once in the tank, due plants scoffing, the chelates breaking down in alkaline conditions and presence of bright light.

This is why EI doses alternate days so the micro does not have a chance to react with the macro phosphate.

I have certainly seen here, peeps with iron deficiencies (in their tank), due to bulk once a week dosing macro and micro and eventually plants suffer iron deficiency of pale yellow/green new growth. Takes a while, maybe a year until all the "other iron" in the tank is exhausted, but was easily fixed by dosing EI properly, on alternate days. I don't think the existing plants recovered too well, as iron is not too mobile in the plants, but all new growth was not iron deficient.


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## GreggZ (9 Jun 2022)

hypnogogia said:


> @GreggZ thank you that is very helpful, by means of the tables you presented.  I have just one further question.
> 
> 
> If it is 12pm, why is the calculation 20er/0.25?  What would it be if it is 15ppm weekly?


User error. I copied an old post where I used 20 ppm as an example. It's fixed above now.


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## GreggZ (9 Jun 2022)

Hanuman said:


> It looks like @GreggZ  got a bit excited and finger happy. It should read:
> 
> 12 ppm weekly at 25% water change is *12* ppm/0.25 = is *48* ppm max NO3 accumulation.
> 12 ppm weekly at 50% water change is *12* ppm/0.50 = is 24 ppm max NO3 accumulation.
> ...


Thanks @Hanuman yes I pulled the trigger too fast and didn't read my own post close enough. Thanks for clarifying.


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## GreggZ (9 Jun 2022)

ian_m said:


> This is why EI doses alternate days so the micro does not have a chance to react with the macro phosphate.


This idea of iron precipitating at the levels we dose has been disproven many times over. Many, many people like myself front load macros and daily dose micros, as do many of the best tanks in the world. Barr himself has endorsed this method. And every all-in-one fertilizer like APT complete has PO4 and iron in the same bottle.


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## John q (9 Jun 2022)

ian_m said:


> This is why EI doses alternate days so the micro does not have a chance to react with the macro phosphate.





GreggZ said:


> Many, many people like myself front load macros and daily dose micros, as do many of the best tanks in the world.



Just to play devils advocate: ~

I wonder if Front loading works better in soft water/ low ph tanks where the precipitation issues are less of a concern?

@GreggZ  I took the liberty of editing macros/micros.  😀


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## tiger15 (9 Jun 2022)

I am surprised to learn that daily dosing without front loading can lead to nutrient dip after WC .  This is the opposite effect of EI intent to maintain stable nutrient levels.  But I guess it is situation dependent as the dynamic of each set up is different depending on one's WC schedule and volume,  high light stems versus low light epiphytes, heavy life stock versus light,  and variability of source water.  The only way to figure out what's going on is to test daily as Gregg did.   Gregg runs a high light Dutch system with heavy life stock, and his source water is purified DI, so it is not an average set up.  

I  front load macros and micros after WC, and supplement with chelated Iron every other day.   I have very heavy life stock of cichlid, and change 75%  water with tap weekly.  My testing showed that N and P are  about same pre and post WC after dosing.   I don't have test kits for K and iron, but my assumption is that K is enough but iron is bio unavailable and therefore I need to dose iron frequently.


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## dw1305 (9 Jun 2022)

Hi all, 


GreggZ said:


> This idea of iron precipitating at the levels we dose has been disproven many times over.


I'm not convinced, mainly because it is the mechanism that <"phosphate stripping"> uses at wastewater plants.  

Are you saying that the phosphate (PO4---) level is to low to precipitate out the iron (Fe+++) ions? or that the HCO3- and OH- ions will mop any ferric iron (Fe+++) ions before the PO4--- ions do?

Anecdotally we have  also have a lot of threads where people (with <"traditional apologies"> to @jameson_uk ) have dosed iron (Fe+++) and still have <"iron deficiency symptoms">, presumably as a result of using a chelator that isn't suitable for <"their water hardness">.

cheers Darrel


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## GreggZ (9 Jun 2022)

dw1305 said:


> Hi all,
> 
> I'm not convinced, mainly because it is the mechanism that <"phosphate stripping"> uses at wastewater plants.
> 
> ...


Darrel I will have to dig up some of my conversations with Barr on this topic. I have them but not at my fingertips. It has to do with the very small relative amounts that we use. Like I said I know many of the best in the hobby who routinely dose macro/micros together and have no issue with iron. It's just not something that successful people I know worry at all about. 

And yes you make a very good valid point that using a source of Fe that is not suitable for the pH of the tank could lead to an iron deficiency. As I am sure you know, EDTA is the source of iron in many commercial micros mixes. It will be most effective at pH less than 6.5. Tanks with higher pH should be using DTPA.

As to "iron deficiency symptoms" that is a topic for debate. Many deficiencies look very much alike. Saying you "see" an iron deficiency and actually having one can be two different things. I have found more often than not when someone claims they see one it can be traced to something completely different. 

Best way to diagnose is to adjust iron dosing (and ONLY iron dosing) and observe.


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## GreggZ (9 Jun 2022)

tiger15 said:


> I am surprised to learn that daily dosing without front loading can lead to nutrient dip after WC .


The principle is really very simple. Let's say you have 40 ppm NO3 in the water column. Remove 50% of the water and replace and you now have 20 ppm NO3 in the water column. Then you dose daily or every other day and the levels slowly rise until the next water change.

But yes as you said much depends on the individual tank. The types of plants, the plant mass, light, CO2, fish load, maintenance habits, etc all play a role. In general I have found keeping levels stables is better in the long run, especially with many harder to grow stems. 

For a tank with with little fish load, even a decently large dose right after a water change can bring the levels back up. Takes some tinkering and a little math to figure out what works best for each tank. If anyone wants the spreadsheet that I posted above PM me and I will send it to you.


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## tiger15 (9 Jun 2022)

But the math only tells you the input,  not the uptake which varies with plant mass, plant health, type of plants, light intensity, CO2 and other variables.  You have super high light, high CO2 injection rate, healthy and hungry stems, so the uptake is on fast lane.   Math can only tell you so much.  Ultimately, actual measurements count most.  Unfortunately, there are no good home testing kits for K, bio available iron, and most micros, so mathematical guessing is the only means.


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## dw1305 (9 Jun 2022)

Hi all,


GreggZ said:


> As to "iron deficiency symptoms" that is a topic for debate. Many deficiencies look very much alike. Saying you "see" an iron deficiency and actually having one can be two different things. I have found more often than not when someone claims they see one it can be traced to something completely different.


Yes I'd agree, there are a lot of deficiencies which <"are difficult to diagnose">, but I think iron (Fe) is possible, mainly because there aren't many nutrients that are <"non-mobile and cause chlorosis in new leaves">. You also have probability on your side, due to the difficulties of keep iron ions in solution.

This is classic <"iron deficiency">.





cheers Darrel


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## John q (9 Jun 2022)

tiger15 said:


> so mathematical guessing is the only means.


A tds meter although by no means precise, helps... on this occasion 🤫


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## ElleDee (10 Jun 2022)

GreggZ said:


> There is simple formula to calculate the theoretical maximum accumulation of fertilizers. It's the weekly ppm divided by the water change percentage.


I may be in my thirties with an MS, but I didn't understand why inverse numbers were useful until I figured all this out. 

I also didn't really get what you meant by target dosing until I started ignoring accumulation altogether and realized I could just do my calculations based on the amount of water I remove. It doesn't matter how big the tank is or what percentage you are changing, you just dose the amount of water you take out to the target. (Obviously there are still the unknowns in play (actual plant uptake and nutrients from fish waste/soil/etc.) that benefit from large WC to keep you at your baseline, but that doesn't affect the calculations.)


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## Hanuman (10 Jun 2022)

tiger15 said:


> But the math only tells you the input, not the uptake which varies with plant mass, plant health, type of plants, light intensity, CO2 and other variables. You have super high light, high CO2 injection rate, healthy and hungry stems, so the uptake is on fast lane. Math can only tell you so much. Ultimately, actual measurements count most. Unfortunately, there are no good home testing kits for K, bio available iron, and most micros, so mathematical guessing is the only means.


Personally I think it's not necessary to do any measurements on ferts specially if you are working with RO. I mean the idea is not to spend the time measuring stuff to the minute details with uptake and whatnot. Every tank will be different, and in fact even one single tank uptake will be different from one week to the other simply because plant grow and consume more. Then you trim.... imagine the headache. The idea with front loading is that all this measurement shenanigans can be put to the trash by doing a simple 80% or even 100% WC  if you can and then dose again to reach the desired levels. Also use the TDS meter once a month to check if it's stable or not. Although it doesn't provide the breakdown of what is in the TDS, watching your plants is enough IMO.
*Edit*: typos/clarity.


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## Ria95 (10 Jun 2022)

tiger15 said:


> I am surprised to learn that daily dosing without front loading can lead to nutrient dip after WC .  This is the opposite effect of EI intent to maintain stable nutrient levels.





tiger15 said:


> But the math only tells you the input,  not the uptake which varies with plant mass, plant health, type of plants, light intensity, CO2 and other variables.  You have super high light, high CO2 injection rate, healthy and hungry stems, so the uptake is on fast lane.   Math can only tell you so much.  Ultimately, actual measurements count most.  Unfortunately, there are no good home testing kits for K, bio available iron, and most micros, so mathematical guessing is the only means.



Absolute stable levels of nutrients was not the intent of EI, but rather "The focus of EI is to ensure that the plants never lack any of their required nutrients. " I still don't see this aim being affected by say 10 ppm NO3 the first day after water change. Many plants won't have issues, but agree with Greggz  that some plants may perform better when dosing high right after the water change.  

When you actually follow the math , you will notice that a tank with supposedly 'uptake on the fast lane'  (such as Greggz's) would benefit less in terms of 'stability' from dosing upfront  then a tank where uptake is moderate or low. Put another way , at the same total dose, the tank is more stable as the uptake % is reduced. Systems with slower growing plants, less light, less CO2 will thus be more stable with adding the total dose right after the water change.  This should be clear, but it's an important point to make. Indeed if the uptake somehow manages to match (or exceed) your total or daily dose and you do 50% water changes with clean water  you will find yourself running out of nutrients fast with math and with testing.



dw1305 said:


> Hi all,
> 
> I'm not convinced, mainly because it is the mechanism that <"phosphate stripping"> uses at wastewater plants.
> 
> ...


It is my understanding that wastewater treatment does not dose chelated iron  and adds an excess of iron to precipitate phosphate out of solution (3:1 molar or thereabout). Even then  it's only a reduction of PO4 not 100% efficient removal.  With a suitable selection of iron chelation  (EDTA; DTPA ,etc) the ~0.5 ppm Fe will be detectable for quite some time in aquarium water with high PO4 ( absent any removal by consumers ofc.). It's not fair to compare our aquariums with the nicely acidified and reducing conditions in a bottle of AIO fertilizers, but still the fear of interaction with PO4 seems to have been exaggerated.


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## dw1305 (10 Jun 2022)

Hi all,


Ria95 said:


> It is my understanding that wastewater treatment does not dose chelated iron and adds an excess of iron to precipitate phosphate out of solution (3:1 molar or thereabout). Even then it's only a reduction of PO4 not 100% efficient removal.


You add soluble ferric chloride (FeCl3) or ferric sulphate (FeSO4) to the wastewater stream and the Fe+++ ions precipitate out the PO4--- as "iron phosphates", which you <"screen out physically">.  The flocculate formation is much more efficient at higher pH values, so normally you add a basic calcium (Ca) supplement (CaO ~ Ca(OH)2) to the waste stream. This gives you a "double whammy" of increased precipitation and a stickier flocculant.


Ria95 said:


> Even then it's only a reduction of PO4 not 100% efficient removal. With a suitable selection of iron chelation (EDTA; DTPA ,etc) the ~0.5 ppm Fe will be detectable for quite some time in aquarium water with high PO4


Exactly that, that was why FeEDTA etc were developed for the hydroponics industry, chelates keep the iron in a plant available (as ions) form.


Ria95 said:


> It's not fair to compare our aquariums with the nicely acidified and reducing conditions in a bottle of AIO fertilizers


That is it as well, keep the conditions acidic and anaerobic and the ferrous iron (Fe++) ions remains in solution.


Ria95 said:


> but still the fear of interaction with PO4 seems to have been exaggerated.


I think some members have seen precipitates forming when they add macro and micro nutrients at the same time, <"possibly when they've been using iron gluconate as their iron source">?

Personally I dose iron by shaking a little bit of FeEDTA into my hand and chucking it in the tank when I remember, so I'm probably not the best person to comment on this thread.

cheers Darrel


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## tam (10 Jun 2022)

If you are dosing the same amount, but either in one go or split equally by day, aren't you either

1. dosing enough daily for the plants to have all they need for the next 24 hours so it doesn't matter if it's lower total at water change as it's still excess of what they need
or
2. not dosing enough in your front load to last the week so they are short the day(s) before water change

As long as it's excess does it matter how much the excess fluctuates? If your daily dose isn't enough to provide an excess, your weekly one won't be either. 

Could front loading showing better results just mean that having enough ferts for the first 4 days of the week and not enough for 3 days results in better growth than not enough on all 7 days and either system would work if you just increased the overall quantity however you split it?


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## ElleDee (10 Jun 2022)

tam said:


> If you are dosing the same amount, but either in one go or split equally by day, aren't you either
> 
> 1. dosing enough daily for the plants to have all they need for the next 24 hours so it doesn't matter if it's lower total at water change as it's still excess of what they need
> or
> ...


I think for a lot of plants it probably doesn't matter, but some species are more persnickety.

There's definitely a number of biological reasons that consistency gives you results beyond meeting basic nutrient demands. For many nutrients plants have different pathways for uptake that they can utilize depending on the conditions. For instance, if concentration of x nutrient is high, the plant might have a preference for pathway y, but if it's lower (but not necessarily deficient) the plant might use pathway z instead. Probably one of those pathways is more efficient than the other, but what is least efficient is having to constantly switch between the two, so if you keep things level you give the plant a chance to optimize for the environment instead of constantly adjusting. There's probably a Barr report that explains this with specific examples.

Again, some plants won't be strongly affected by this, so if what you are doing is working I wouldn't change it, but if you are having issues with specific plants or feel like your tank has room to improve it's something to consider.


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## tiger15 (10 Jun 2022)

tam said:


> If you are dosing the same amount, but either in one go or split equally by day, aren't you either
> 
> 1. dosing enough daily for the plants to have all they need for the next 24 hours so it doesn't matter if it's lower total at water change as it's still excess of what they need
> or
> ...


Gregg has demonstrated that front loading macros after WC will provide even distribution of around 16 ppm N daily throughout the week, whereas daily split loading of the same amount will provide 5 ppm N on day 1 and progressively build up to 17 ppm on day 7 before the next WC.   Even with a dip to 5 ppm on day 1, there is still surplus N to satisfy EI excess approach and  way above ADA lean dosing approach.    Note that Gregg’s finding is unique to his set up that may not necessarily be replicable to other set ups.

I always front load nutrients except for iron due to Fe  short bio availability time span.  I didn’t monitor nutrient levels as detail  as Gregg  but  my measured pre and post WC N after dosing is consistently around 10 ppm, so I assume the daily distribution  is fairly even.   I grow medium light slow growing plants but my life stock, mostly cichlid, easily double  that of Gregg..


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## GreggZ (10 Jun 2022)

Ria95 said:


> When you actually follow the math , you will notice that a tank with supposedly 'uptake on the fast lane'  (such as Greggz's) would benefit less in terms of 'stability' from dosing upfront  then a tank where uptake is moderate or low. Put another way , at the same total dose, the tank is more stable as the uptake % is reduced. Systems with slower growing plants, less light, less CO2 will thus be more stable with adding the total dose right after the water change.  This should be clear, but it's an important point to make. Indeed if the uptake somehow manages to match (or exceed) your total or daily dose and you do 50% water changes with clean water  you will find yourself running out of nutrients fast with math and with testing.


Good point but if I can add on to this thought you also need to take into account fish load.

@tiger15 is right every tank is different.

Let's take my example from above, but change the fish generated NO3 from 2.25 daily to 0.5 daily. So basically my tank but with very little fish load. In order to keep NO3 somewhere around the 16-17 ppm range I would be better off with a large dose after a water change and then two smaller doses during the week. Also note I have to change my NO3 dosing from 12 ppm to 21 ppm to keep the same ppm in the water column.

So the bigger point is that when  you see someone else's dosing, you need to take everything into account when you compare it to your own tank. It would be better if everyone would just report the level that they would like to keep the water column at. I've been on this crusade for years but old habits die hard. But that being said I do see more and more people adopting this philosophy and know quite a few people using it now.


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## tiger15 (10 Jun 2022)

Yes, with life stock, the math is more complicated as you need to account for tank generate N from fish food and waste, not easy.   I’m not sure how Gregg estimated his tank generated N and plant uptake.

I can figure out mine easier since I keep a record of nitrate testing for decades  before I grow plants.  My nitrate level  was between 60 to 80 ppm just before weekly 75% WC, and I haven’t changed my WC habit after growing plants and keep roughly the same fish stock,   With known dosing rate and WC rate, I can back calculate the plant uptake rate.   The uptake rate  is substantial because, with plants my pre WC nitrate is around 10 ppm, meaning that 50 to 70 ppm has been uptaken. There are complication factors such as denitrification,  decaying plant and detritus nitrification that are unaccounted for, and fish stock then and now is not  equal.  It’s all mathematical guessing except for the direct nitrate measurements.


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## John q (10 Jun 2022)

tiger15 said:


> I’m not sure how Gregg estimated his tank generated N and plant uptake.


I think he waved his fingers in the air and multiplied it by 3 to the power 2.  

I honestly suspect, like you he methodically tested and came up with some numbers, and then took it Upon himself to ...  spread the word.


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## Ria95 (11 Jun 2022)

tiger15 said:


> Yes, with life stock, the math is more complicated as you need to account for tank generate N from fish food and waste, not easy.


It adds a variable, but a high initial dose after the water change will still make the values more stable.
Taking the example from Greggz' table, you can join the 2 values into 'daily  NO3 dif.' value, where 'Daily NO3 dif' =  'Daily Tank Generated NO3' - 'Daily NO3 Plant Uptake'.  This value can be positive or negative.
When plant uptake >  N  production  the  |"NO3 dif"| is a smaller % of the  weekly dose then plant uptake alone. In effect you model less NO3 loss per day.  As mentioned above this results in  more stable values.
When plant uptake < N production, the "NO3 dif"  is in effect a daily dose. This daily dose would take place regardless of when we add fertilizer. However, if we add fertilizer daily we would only add to the daily dose. Adding fertilizers after a water change will still give a smoother graph.


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## GreggZ (11 Jun 2022)

John q said:


> I think he waved his fingers in the air and multiplied it by 3 to the power 2.
> 
> I honestly suspect, like you he methodically tested and came up with some numbers, and then took it Upon himself to ...  spread the word.


My numbers are estimates based on observations and measurements from many, many years of keeping a planted tank. I don't claim that they are precisely accurate, more like a reasonable assumption.

But I can tell you this. If I test NO3, no matter what day of the week, the reading looks pretty much exactly the same. And my TDS is almost exactly the same right before and right after a water change.


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## Hanuman (11 Jun 2022)

LOL guys, lots of brainw***ing going on here for a Saturday....
Frontload, forget it. Rinse repeat every week. Enjoy.
The end. 😘


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## tiger15 (11 Jun 2022)

Ria95 said:


> It adds a variable, but a high initial dose after the water change will still make the values more stable.
> Taking the example from Greggz' table, you can join the 2 values into 'daily  NO3 dif.' value, where 'Daily NO3 dif' =  'Daily Tank Generated NO3' - 'Daily NO3 Plant Uptake'.  This value can be positive or negative.
> When plant uptake >  N  production  the  |"NO3 dif"| is a smaller % of the  weekly dose then plant uptake alone. In effect you model less NO3 loss per day.  As mentioned above this results in  more stable values.
> When plant uptake < N production, the "NO3 dif"  is in effect a daily dose. This daily dose would take place regardless of when we add fertilizer. However, if we add fertilizer daily we would only add to the daily dose. Adding fertilizers after a water change will still give a smoother graph.


I don't think you can generalize.  Your complex math logic needs to be validated by measurements as each set up is different and there are many variables.  Mine and Gregg's setups turn out to be true perhaps because we both stock heavily.


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## JoshP12 (12 Jun 2022)

Hanuman said:


> LOL guys, lots of brainw***ing going on here for a Saturday....
> Frontload, forget it. Rinse repeat every week. Enjoy.
> The end. 😘


😂 … I front load as well! I mean at the moment I’m the overgrown pantanal and don’t do anything but soon when I rescape!

We can discuss the sciencey piece but what about the living piece?

I wouldn’t be surprised if every week for months you go back to the same targets, the plant somewhat plans for it - it’s all predictions … but the “dip/change in consumption that is expected/guessed” probably converges to a value

What I mean is the plant probably plans what it does based on being given the same thing for months … while taking inventory of soil conditions etc.

We plan our futures, finances, diets, careers to obtain desired outcomes … certainly we are more advanced beings but plants are pretty darn smart too.

Sunday morning coffee …

Oh and that’s why I front load haha - it’s like a universal basic income … any extra comes from my fish food! Haha


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## Hanuman (12 Jun 2022)

JoshP12 said:


> certainly we are more advanced beings


Not sure about that in all honesty considering how disastrously we have managed our planet so far and how so predictably we will end up swimming quite literally in our own s***t. Yes, I'm not an optimist when it comes to human kind.


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## Ria95 (13 Jun 2022)

Tend to agree with you there Hanuman.  The world is looking more and more like a certain movie prediction. We are at the point where addition and division are considered complex math.


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