What time of the day do you dose the fertilizer?

[j.c.koh]

This is an interesting topic that I always get different answers when researching on them.

Hopefully can get some discussions over here as the forums are getting very quite recently.

For me I dose my fertilizers when the lights are on base on the theory that plants are active and start absorbing nutrients on the daytime and resting/sleeping at night, doing so leaves little to none excess nutrients for the algae to feed on. Some dose 2 hours before light's on to allow them to mix well in the water 1st.


There is an interesting theory that makes perfect sense but directly contradicts my routine.

They claimed that plant absorbs nutrients 24/7 so it doesn't matter what time you dose the fertilizer however, because during photo period plants were busy interacting with the co2 in the water they barely had enough time to absorb the fertilizer properly causing some to get used up by the algae. Plants are not good at multi-tasking.
They dose it in the evening when the plants are not distracted.

Both made sense but which is better?

[jackychun]

Hi bro JC,

It is a good topic to discuss on.

For me, I dose the fertilizers mostly before I go to work in the morning or at my convenience. Normally it takes only 3 mins to dose for all the tanks I got.

At that timing, there is tank which has light on, and some are still off. Base on my observation, the plants are still have healthy growths. So I guess as long as the water body has nutrients readily available, plants will find the way to get it. We have different plants in the tank, so the way they take up nutrients is different as well. Some of them prefer to have nutrients from the substrate by roots , others might take it from the leaves, direct from the water body.

That is just my observation and experience base on my tank only. I don't really have details study about it. That would be good to know more about others experience.


Sent from my iPhone using Tapatalk

[j.c.koh]

Thanks for sharing jacky, I always wondered how you dose your fertilizers.

[torque6]

With reference to Tom Barr, "Concentration drives uptake of nutrients up to non-limiting point. In other words, growth is controlled not by the total amount of resource available but by the limiting factor. Day or night does not matter."


The brief equation should be :
Dose = exposure(Time) X concentration(ppm)


It's called Liebig's law of the minimum


https://en.wikipedia.org/wiki/Liebig...of_the_minimum

But I dose it every morning before I go to work and at night when I forget....

[Zep]

Good topic. I was reading up on this too. And saw Tom
Barr's post that the time of dosing does not matter.

I usually dose my ferts in the morning before I go to work at about 7am. Lights get turned on only at 2-3pm. Then I decided to try dosing at night. So I tried it out by dosing every night just after lights out at 9pm. Did that for a few weeks but didn't really see any noticeable difference.

I guess it's a matter of whichever time is more convenient for you.

[j.c.koh]

@zep,

Thanks, it's good to have a testimony of someone who tried 2 different methods and made a comparison.

@torque6,

Tom barr is the rock star of the aquascaping world, he's often mentioned in forums, ie dosing and always had solid evidences to back up his claims. I had read through some co2 and bba posts made by him. I didn't know about the liebig's law of the minimum, I'm glad you shared with us.

I do not understand the equation lol, but I do understand the theory through the liebig's barrel explanation.
Following the principles of the theory: 'plant's growth is limited by the nutrient in shortest/sacarcest supply, a chain is only as strong as the weakest link' allows me to balance the tank more efficiently.

I understand that the concept was originally applied to plant and crop growth and was criticized and rejected many times, but I think Tom barr's stunning algae free tanks speaks for themselves.

Originally the pursuit for the perfect dosing timing is because I do not believe that the timing doesn't matter.

Because plants behaved differently day and night and the water chemistry is different with and without lights and co2 surely there must be a certain time of the day where plants would absorb faster.

Maybe the differences is too insignificant to be bother.
But I'm glad I started this thread is not I wouldn't learn about the liebig's law.

[jackychun]

BTW, other than the timing that I mentioned in my previous post, I also have the habit to dose fertilizers immediately after I have water change for the tank.
IMO, it is good to have the nutrients readily available for plants to uptake right after water change.

[j.c.koh]

Ya it make sense,

I always try to do water change before light's on in the morning, afterwards I would dose immediately after the light is on.

Sometimes when I'm busy I would do water change in the evening, but because of the light's on dosing rules I'm following I always wait till the next morning before dosing.

Next time if I do water change in the evening, I would dose straight after.