# Is there any need for a rest day in EI dosing?



## Ady34 (16 Jul 2012)

Hi,
just got round to dosing EI macro/micro ferts on alternate days but noticed that in the dosing regimes it says 3x weekly for each leaving a fert free day or 'rest day' as ive seen it called before. Is there any actual reason to leave a rest day rather than just continue the cycle? Im presuming the only downside is financial?
Cheers,
Ady.


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## Westyggx (16 Jul 2012)

I read that this rest day is used so that your tank can use up all the ferts in the water collumn, probably wrong though!


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## chrisjj (16 Jul 2012)

And getting confused what to dose on what day!

One bottle has in big writing: Monday / Wednesday / Friday, the other: Tuesday / Thursday / Saturday, so I don't get confused!


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## Ady34 (16 Jul 2012)

Westyggx said:
			
		

> I read that this rest day is used so that your tank can use up all the ferts in the water collumn, probably wrong though!


my theory is if i just continue it ill be less likely to forget and there will always be an excess, covering any shortfalls, increases in plant mass etc...


			
				chrisjj said:
			
		

> And getting confused what to dose on what day!
> 
> One bottle has in big writing: Monday / Wednesday / Friday, the other: Tuesday / Thursday / Saturday, so I don't get confused!


yeah there is that of course, however sometimes early in the morning i dont know what day it is


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## ian_m (16 Jul 2012)

If you plough through all the EI documentation, especially some of the early stuff, they talk about *daily* dosing of macro and micro. In later documents it drops to once every two days along with when you feed your fish, every two days, just to make things easier.

In the end I don't think the plants know or care, the aim being to ensure the tank never runs out of nutrients.


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## Morgan Freeman (16 Jul 2012)

ian_m said:
			
		

> In the end I don't think the plants know or care, the aim being to ensure the tank never runs out of nutrients.


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## Ady34 (16 Jul 2012)

ian_m said:
			
		

> If you plough through all the EI documentation, especially some of the early stuff, they talk about *daily* dosing of macro and micro. In later documents it drops to once every two days along with when you feed your fish, every two days, just to make things easier.
> 
> In the end I don't think the plants know or care, the aim being to ensure the tank never runs out of nutrients.


yeah i think most people dose adjusted amounts of macro and micro on alternate days to avoid having to purchase additional chemicals to prevent the precipitation of ferts when dosed daily together. All in ones such as tpn+ etc contain 'stuff' to stop this but when dosing EI its just something else to buy which is an unnecessary cost when you can just dose them on seperate days.
I agree though that the aim is to ensure the tank never runs out of nutrients, so if i just continue 7 days a week all will be good


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## Iain Sutherland (16 Jul 2012)

dont think it has any bearing at all.

I have 2 rest days and dose trace on tuesdays and thursdays, easy to remember.


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## hinch (16 Jul 2012)

short answer is nope no need. 

there's also no need to dose separate micro/macro/trace etc, there's also very little harm in massively overdosing.

The only catch is you need to be doing the weekly water change as that removed the excess minerals and mostly resets the tank parameters.


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## Morgan Freeman (16 Jul 2012)

hinch said:
			
		

> The only catch is you need to be doing the weekly water change as that removed the excess minerals and mostly resets the tank parameters.



My understanding was that it removes the waste produced by the plant growth. Why would you need to remove excess minerals? What does reset the tank parameters even mean?


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## ian_m (16 Jul 2012)

Ady34 said:
			
		

> yeah i think most people dose adjusted amounts of macro and micro on alternate days to avoid having to purchase additional chemicals to prevent the precipitation of ferts when dosed daily together. All in ones such as tpn+ etc contain 'stuff' to stop this but when dosing EI its just something else to buy which is an unnecessary cost when you can just dose them on seperate days.


Not true. Adding macro and micro to tank at same time is OK, they just get in tank diluted not a problem.

This issue is putting macro and "cheaper" micro in same bottle the chelated iron precipitates out as insoluable and plant unusable iron phosphate. You can use a different form chelated iron (and keeping it acid) that won't precipate out with macro salts to make an all in one mix as an alternative.


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## ceg4048 (16 Jul 2012)

Hello,
         None of these theories are valid. The theory about excess minerals is especially off the mark because the dosing program is based fundamentally on dosing more that you think you need. If you are still thinking in terms of getting rid of excess minerals then you are really lost in deep space. As mentioned by Morgan the idea is to clean the tank of defecation and urination which builds up to toxic levels.

The reason for rest days is simple arithmetic. You don't need to dose on the "rest" days simply because the target weekly concentration is reached within 5 days instead of within 7 days. If a week had only 5 days then you would be dosing every day. But since a week has 7 days, and since one of those days is a water change day, it makes no sense to design a dosing program that doses before you change the water and then forces you to dose again after you change the water.

If you want to do daily dosing then you would just divide the target weekly concentration numbers by 7 and it will tell you how much to dose per day. This is not rocket science folks. You have a target amount of powder and you have so many days, during a repetitive cycle, in which to dump them into the tank. The pattern that was accepted is that which was most logical. How many meals per week do you eat and how do you distribute those meals? If you eat 3 per day and if you repeat that 7 days a week you normally will not starve to death. Wasn't that easy to figure out?

Cheers,


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## Ady34 (16 Jul 2012)

ceg4048 said:
			
		

> Hello,
> None of these theories are valid. The theory about excess minerals is especially off the mark because the dosing program is based fundamentally on dosing more that you think you need. If you are still thinking in terms of getting rid of excess minerals then you are really lost in deep space. As mentioned by Morgan the idea is to clean the tank of defecation and urination which builds up to toxic levels.
> 
> The reason for rest days is simple arithmetic. You don't need to dose on the "rest" days simply because the target weekly concentration is reached within 5 days instead of within 7 days. If a week had only 5 days then you would be dosing every day. But since a week has 7 days, and since one of those days is a water change day, it makes no sense to design a dosing program that doses before you change the water and then forces you to dose again after you change the water.
> ...


Cool, so the reason for the rest days is down to target reaching and simplicity, but going above and beyond these targets is perfectly acceptable. 
I know in another thread the EI was discussed in terms of an excess, but as a minimum required excess which may need adjusting up to compensate for increased growth rates, plant mass etc. So i was thinking dosing the extra day/days would cover all the bases, including negating 'topping up' of ferts after a water change.


			
				ian_m said:
			
		

> Ady34 said:
> 
> 
> 
> ...


Is this a definative answer then and you can infact dose macro and micro daily together if you choose? Im convinced that my recent dosing of macro/micro one after another lead to poorer plant growth which i put down to deficiencies caused by precipitation of some ferts? Since dosing alternately things seem to have improved....but maybe im willing it to be that way  :? 
Are you saying that with the dilution of large volumes of tank water this negeates the precipitation effect?
I have bought chelated iron to dose alongside my macro and micro mixes, which im going to add twice weekly. I also dose easy life potassium 2x week (maybe unnecessary now). So again it doesnt matter on which days (either macro or micro) i dose these? I want to cover all possible nutrient deficiencies.
Sorry, for the repeated questions, but i just want to get my head around the effects of precipitation and when i should be dosing what   
Cheerio,
Ady.


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## ceg4048 (16 Jul 2012)

Ady34 said:
			
		

> ...I know in another thread the EI was discussed in terms of an excess, but as a minimum required excess which may need adjusting up to compensate for increased growth rates, plant mass etc. So i was thinking dosing the extra day/days would cover all the bases, including negating 'topping up' of ferts after a water change...


Well, I mean what bases are there to cover? The tank tells you when it is running low. All you have to do is look at it. I suppose you can belt and brace something until you can no longer move. If you dose an extra day then the plant grows more, forcing you to add even more, so you wind up in this seemingly endless "do loop" where you have to add more in order to support adding more. More maintenance, more trimming, more everything. I only add more if I need to, not in anticipation of needing to. That's just crazy. When I do 3X and 4X EI it's either to prove a point that nutrients don't cause algae - without reservation, or to actually fix a deficiency problem that is clearly exhibited in the tank, or in order to support insane lighting intensities. If you like doing water changes and trimming every week you can go for adding more and more, but at some point you'll probably decide that you want to get a life. It's "supposed" to be a nice thing to not have to worry about dosing a day or two. Go play football, or attend a head banger concert, or go on a date with that cute babe in the bikini discreetly shown on whitey89's Ryahoo journal. Let's keep it real.



			
				Ady34 said:
			
		

> ian_m wrote:
> 
> Ady34 wrote:yeah i think most people dose adjusted amounts of macro and micro on alternate days to avoid having to purchase additional chemicals to prevent the precipitation of ferts when dosed daily together. All in ones such as tpn+ etc contain 'stuff' to stop this but when dosing EI its just something else to buy which is an unnecessary cost when you can just dose them on seperate days.
> 
> ...


Well, I think people get confused and they mix and match different issues, Or they pick up on only part of a problem and miss the big picture. Dosing micros and macros is NOT a good idea simply because of the risk of precipitating iron and phosphate. It's a real possibility because of the characteristics of both Iron and PO4. This doesn't mean that it will always happen. A lot depends on the other water parameters. It happens more frequently in hard water than it does in soft water for example. It happens more frequently in higher pH as opposed to lower pH. So because we can't predict what kind of water a hobbyist will have we just make a general rule to say try and avoid dosing these to products together unless you add acids to help the chelation. Sometimes, your EI mix is so concentrated that even if it happens, and you get some precipitation, you still have enough Fe and PO4 left in solution. We just cannot predict every conceivable scenario, so we make a general rule of thumb to reduce the possibilities of negative consequences as much as possible.

It has nothing to do with "cheaper micro". EDTA is a common Fe chelating agent but is less effective when the water is hard, and so those people with hard water often see the cloudiness, which are the precipitates of Fe/PO4 from failed chelation under those chemical conditions, so DTPA and a few others can be used. Are they more expensive? Maybe, but DTPA works better than EDTA in hard water. The Iron inside is the same. If you have soft water then EDTA works fine and you would never know the difference. So cheap or expensive is completely irrelevant because reactions are a function of the water's chemistry as well as the properties of the chelators themselves.

Cheers,


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## Ady34 (16 Jul 2012)

ceg4048 said:
			
		

> Ady34 said:
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Ok,...but theres no harm in doing it   
I thought my light would dictate my growth rates, and much like c02, the ferts are used in relation to these demands  :?  Im sure it is all far more intricate an interaction for me to ever get my head around hence why it is simplified in the ways we are taught. I think its probably a case that if everything the plant needs is offered in abundance, then increasing any one of the light, c02, fert triangle will result in accelerated growth....but i still struggle to get one right, hence why i want to reduce the chances of fert issues while i concentrate on getting the rest right. My next scape im going to play around with single water return direction (lily pipe...  ), greater surface agitation and im also going to raise the height of my lighting unit in hope of reducing the demand for c02 as i dont like it so on the edge with the acceptable levels for the fish....hopefully all to give a little more leaway.
As for making life easier and not having to worry about it for a day or two, its no hardship, dosing takes a few seconds and i tend to prefer the continuity as it prevents me from getting out of the routine which would probably lead me to forget more than a couple of times   
This is my hobby now, football is an activity of the past due to an ankle injury, im not really that into music, but a date with that bikini clad babe sounds like a nice alternative   



			
				ceg4048 said:
			
		

> Ady34 said:
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yeah, thats more as i understood it. I knew something was going on as the floating plants were suffering too and i had a noted increase in GSA. Floaters, as with most of the plants, are doing much better again now with seperate day dosing, the GSA ill just have to wait and see. Whatever the reasons, all ive changed is the dosing routine so really its all it can be, even in my soft acidic water.
Thanks again Clive, as always its valuable information   
Ady.


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## Nathaniel Whiteside (16 Jul 2012)

ceg4048 said:
			
		

> .. or go on a date with that cute babe in the bikini discreetly shown on whitey89's Ryahoo journal. Let's keep it real.



Oiii thats me and my bird


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## Iain Sutherland (16 Jul 2012)

:idea:  that might be why i used to get cloudy water from time to time in my old tank.  Had put it down as mystery but maybe it was the days i missed dosing and did it together when i was lazy.


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## ceg4048 (16 Jul 2012)

Ady34 said:
			
		

> Ok,...but theres no harm in doing it
> I thought my light would dictate my growth rates, and much like c02, the ferts are used in relation to these demands :? Im sure it is all far more intricate an interaction for me to ever get my head around hence why it is simplified in the ways we are taught. I think its probably a case that if everything the plant needs is offered in abundance, then increasing any one of the light, c02, fert triangle will result in accelerated growth....but i still struggle to get one right, hence why i want to reduce the chances of fert issues while i concentrate on getting the rest right.


Yep, you're right in that there is no harm in adding more, but again, in the general case where the average person would appreciate the day off, all they would have to do is to increase the dosages on the 5 days and that would accomplish the same thing. Also, we have to be careful that we don't allow ourselves to turn into a yo-yo. As we've said many times, light is indeed at "the top of the food chain" and the schematic is usually shown as:
Light====>Carbon===>Nitrogen==>Phosphorous==>Potassium=>Traces

So it's easy to conclude that the "machine" is always driven from the left to the right all the time. But there is a subtlety. You can actually drive the equation from right to the left in some places, so that the schematic is best described with double headed arrows:
Light><====>Carbon<===>Nitrogen<==>Phosphorous<==>Potassium=>Traces

What I'm trying to show in the second schematic is that the abundance of some elements actually drive the uptake demand in the opposite direction. Adding more P actually drives the plant to uptake more N. There is a scenario in which your N dosing may be marginal and you then add a lot of PO4. It's possible to actually drive the N uptake such that the plant actually begins to suffer an N shortage. Extra PO4 can therefore expose the fact that your N dosing is marginal, whereas if you had not increased the PO4 you might not have seen the plant display poor N uptake. So this has happened where someone adds PO4, sees the plant yellowing and draws the conclusion that adding PO4 causes yellowing, instead of realizing that they were not adding enough NO3 for the amount of PO4 being added.

Likewise, you can add a lot more N and this drives the plant to demand more Carbon. So if CO2 were marginal to begin with adding more N might reveal a CO2 shortfall.

The only place the madness ends is on the far left where I show the "><" link between Carbon and light. This too works both ways, but Barr has shown that adding more carbon can decrease the demand for light. In high carbon concentrations the plant does not need to expend energy building light gathering protein structures, so you can use less light and make better use of the available light.

This is one of the reasons that people decide to back away from eutrophic dosing. Tanks can easily become victims of their own success, so they back off from the high lighting, accept slower growth rates and they find that their is a greater range of acceptable concentrations which minimizes the deficiency syndromes in the tank. It also possibly helps to satisfy the craving for bright lights if they use the bulbs that have a high green/yellow content, so that they can use lower wattages (or less number of bulbs) but yet the tank still appears to be bright.



			
				Whitey89 said:
			
		

> Oiii thats me and my bird


A thousand pardons mate.  I thought you might have Photoshopped that in for better thread viewing numbers. It was monochrome you see. A classic marketing ploy. 

Well at least we know now that it won't be like LondonDragon's tedious journal. 85 pages and not one snap of the GF (very disappointed Paulo!) When asked to throw us a bone he posted a picture of some boring pet dog scratching on the sofa. Viewers are hereby encouraged to lodge formal complaints. Boo!

Um...anyway, yeah, nice placement of the rocks, well done mate. Should be a stunner when it fills in. 

Cheers,


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## Nathaniel Whiteside (16 Jul 2012)

Haha! Thanks clive  

Keep overloading my head with your unrivalled amount of planted tank knowledge!
 I need it & maybe, just maybe, one day I may understand most of it


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## Ady34 (17 Jul 2012)

ceg4048 said:
			
		

> What I'm trying to show in the second schematic is that the abundance of some elements actually drive the uptake demand in the opposite direction. Adding more P actually drives the plant to uptake more N. There is a scenario in which your N dosing may be marginal and you then add a lot of PO4. It's possible to actually drive the N uptake such that the plant actually begins to suffer an N shortage. Extra PO4 can therefore expose the fact that your N dosing is marginal, whereas if you had not increased the PO4 you might not have seen the plant display poor N uptake. So this has happened where someone adds PO4, sees the plant yellowing and draws the conclusion that adding PO4 causes yellowing, instead of realizing that they were not adding enough NO3 for the amount of PO4 being added.
> 
> Likewise, you can add a lot more N and this drives the plant to demand more Carbon. So if CO2 were marginal to begin with adding more N might reveal a CO2 shortfall.
> 
> ...


ahh, s**t, its all too complicated, maybe best off sticking to the minimum EI excess and adding more if a deficiency becomes evident as you have already suggested...otherwise you could end up chasing a never ending equilibrium of fert concentrations, each having a knock on effect to another     I suppose thats where the watching your tank becomes so important as the plants tell you everything you need to know...presuming you can correctly diagnose the problem.....ahhhhhhh   
Mind you, that does seem more relevant to those who dose each fert individually in response to an issue, as most of us just follow the set guidelines of quantities. Can it not be as simple as adding for example double the dosage of everything if an issue becomes apparent. ie the concentrations of each individual fert kept the same % wise, but each of them doubled to give a stronger solution but at the same ratios (6 tsp, becomes 12 etc but for each element)...or when you start providing more for the plants does their uptake rate change to throw off the recommended ratios? Logically youd think that if the ratios were kept the same as the standard recommendation that there would still be enough of everything so as not to leave a shortfall/deficiency. I think really what im trying to say is if your dosing ei standard ratio and see a deficiencey that it would be best to not just treat that symptom by for example adding more P, but to add more of everything to ensure that that P deficiencey when treated does not then manifest itself in an N deficiency.....ahh, but then i see you may then suffer a Carbon deficiency so it just isnt that straightforward, then you need to slow it all down by reducing the light so you can lower the required amounts of everything in a manageable way.....you have to find the right balance for your individual tank, and is the reason many advocate lower lighting levels so as not to push the limits and in effect to keep thing simpler and easier to manage....as you said   
It seems that reducing lighting intensity is in fact the best course of action to remedy most tank issues. It is both the minimiser and maximiser of all planted tank problems   
Got there in the end, i could have deleted all this now, but because i have written it i dont want too   
Think thats whats called writing down working through your thought process  :? 
Night Night    :silent: ,
Ady.


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## Ady34 (17 Jul 2012)

so, 
in answer to the q 'is there any need for a rest day in EI dosing?', the answer is no there isnt, however it may cause issues, think of the analogy 'if it aint broke dont fix it', as if you try to fix it when it isnt broken you will maybe break it. If you do break it, try to fix it not by adding more ferts, but by reducing lighting and going back to your original dosing...its easier that way   
Ady.


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