Daily vs Weekly dosing & water changes

onetwothree

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3 Jan 2020
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Location
Leeds
Hi all,

I've had a search for this topic but couldn't find much specific to my question.

Most of the ferts dosing is done on a weekly basis (according to the bottle), I know you can do it daily if desired. I've started doing it weekly just for convenience at the moment, but I do water changes maybe every other day of around 10-20%.

Is this dosing based on the idea that most people do a large water change at the end of the week, and then re-dose? In which case, they're topping up straight after removing water. In my case, should I slightly increase the dose as I'm actively reducing it on a continuous basis before its next dose anywhere from 6-1 days later? Alternatively, should I drop around 10% of a dose each time I remove about 10% of water and then the remainder of the dose at the end of the week for example?

My concern is that with the frequency of changes, I'm basically under-dosed for several days at a time before I do another weekly dosing etc.

Any advice appreciated.
 

ceg4048

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Staff member
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11 Jul 2007
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8,993
Location
Chicago, USA
Hi all,

I've had a search for this topic but couldn't find much specific to my question.

Most of the ferts dosing is done on a weekly basis (according to the bottle), I know you can do it daily if desired. I've started doing it weekly just for convenience at the moment, but I do water changes maybe every other day of around 10-20%.

Is this dosing based on the idea that most people do a large water change at the end of the week, and then re-dose? In which case, they're topping up straight after removing water. In my case, should I slightly increase the dose as I'm actively reducing it on a continuous basis before its next dose anywhere from 6-1 days later? Alternatively, should I drop around 10% of a dose each time I remove about 10% of water and then the remainder of the dose at the end of the week for example?

My concern is that with the frequency of changes, I'm basically under-dosed for several days at a time before I do another weekly dosing etc.

Any advice appreciated.
Hi,
It's very difficult to provide a concrete answer because first of all, no one truly knows the composition of your water. It would require very expensive equipment to determine. Unless you are replacing the removed water with RO it could easily be that your water addition is adding nutrients, for example. Many a tap water contain a wide range of nutrients.

This was an especially difficult topic during the advent of EI when we advocated it's simplicity and reliability. others argued that they added no nutrients at all and yet their plants were healthy. If their tap water was rich in nutrients then it was clear that they did not need to use EI as they were provided the benefit of free dosing from tap.

In any case, as you can see, we wrap ourselves around the axle attempting figure out something that should be simple.
The mathematics of water removal and concentration is too much of a puzzle.

If you wish to continue weekly dosing then just add up the amounts from the bottle suggested daily values and dump that calculated amount in at the regularly scheduled day. If deficiencies appear then just double the amount. Easy.

So the first step is to simply note the health of your plants under your chosen dosing scheme. If there are no symptoms of nutrient deficiency then there is nothing else to worry about. Simply carry on. As the plants bulk up and create more mass you may start to see deficiency syndromes which can easily be addressed either by increasing your quantity level or by more frequent dosing.

Cheers,
 
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