Stable nutrient dosing using hobbyist test kits

[Dennis Wong]

I fully agree with the concept Rocco !

But when you don’t know about that and you follow the advice of say APT fertilizer for exemple, it say to dose 3, 4 times or every days of the week , but not replenish what the water change remove !

You know what i mean ?

APT3 aims to be zero bound so there is no need to replace nutrients during water changes. APTe has an updated page on how to use it precisely, whether on a zero bound system or at an elevated level.

 

[JayP]

APT3 aims to be zero bound so there is no need to replace nutrients during water changes. APTe has an updated page on how to use it precisely, whether on a zero bound system or at an elevated level.

Doh! I've been double dosing APT3 on water change days since the start, and I dose every day.

 

[Mitelog]

APT3 aims to be zero bound so there is no need to replace nutrients during water changes. APTe has an updated page on how to use it precisely, whether on a zero bound system or at an elevated level.

If the aims is to be zero bound Dennis, what is the logic of the very high potassium level in your product ?

From previous ICP testing on my old tank, potassium is consumed at a rate around 0,4 to 0,6 ppm per day when my no3 consumption was between 2 and 3 ppm per day.

So if your product introduce around 2,5 ppm K+ per day, there will be an accumulation of k for sure ?

 

[Dennis Wong]

Yes there is generally K accumulation, since lack of K seems to be the number 1 fear in the aquatic hobby, and having some excess K doesnt cause any significant issues to most plants.

 

[Mitelog]

Ok thank’s ! good to have your view on that.

 

[Mitelog]

Out of interest Dennis, (sorry i’m too curious ) i have seen in your journal about the 60liters tank that you put some data about potassium, ammonium etc at the start of the journal, it seem you use a photometer to have this accuracy right ?

Can you tell me what is the average consumption of potassium in a 24h period in your tank ?

I know it depend of many things but it’s just out of interest.

 

[That Guy Brian]

Doh! I've been double dosing APT3 on water change days since the start, and I dose every day.

Out of curiosity, have you noticed any change after stopping the front loading after a water change? I don't quite understand how @Dennis Wong is suggesting that there is no need to front load. My brain says that if there is a 50% water change, you immediately need to replace 50% of the ferts.

-B

 

[JayP]

Out of curiosity, have you noticed any change after stopping the front loading after a water change? I don't quite understand how @Dennis Wong is suggesting that there is no need to front load. My brain says that if there is a 50% water change, you immediately need to replace 50% of the ferts.

-B

I haven't stopped.

Dennis knows his stuff, but for my tanks, no need to fix something that's not broken.

 

[Koan]

suggesting that there is no need to front load

The point of this post is to give a more granular approach, in order to accomplish the goal of actual stability on a day-to-day basis.

He doesn't say not to front load. His point is you need to be careful how you go about choosing much you're loading, that it needs to be based on how much your plants are actually eating :

If you are doing say a 50% water change, and your water has 20ppm of nitrates before the water change, you would want to dose back 10ppm of nitrates back to keep nutrient levels stable at 20ppm. If your target level is 15ppm of nitrates instead, then after a 50% water change (removing 10ppm from 20ppm), you will need to dose back 5ppm of nitrates instead. Over the long run, the goal should be to keep levels the same before/after water changes.​

If this is confusing, have a look at the article about nutrient stability to get more context:

Why nutrient level stability matters for planted aquariums

Nutrient stability in planted aquariums - how to have stable nutrient levels and why it is important. Avoid triggering algae and tip stunting.

www.2hraquarist.com

 

[Mitelog]

My brain says that if there is a 50% water change, you immediately need to replace 50% of the ferts.

-B

It seem « ideal »from the stability point of view but….
Since 2 weeks i keep my parameters in a very narrow range : NO3 at 10ppm, PO4 at 0,6 and k at 15ppm.
I does that by changing 90% of my water at the start of the first week and the week after i changed 50% water but i front loaded enough to keep my NO3 at 10 ppm( same method for the others macro)

By dosing daily, what the plant « eat » every days ( approx. 1 ppm NO3 and 0,5 ppm PO4) my level have stayed constent ( between 9,6 and 10,4 for the no3 during the full week ), since i have the Hanna checker photometer NO3 and PO4, i can have a pretty accurate measure

My plants have evolved very little during those 2 weeks even if my parameters stayed constant ! The leaves from the previous 2 weeks begin to be attacked by algae, some tip stunting etc…. In short, nothing have changed !

In the past when i used EI : 3 times per week dosing and 50% changes with no front loading, i had stellar plant, full of color, no tip stunting and no algae ! And i ´m certain my parameters was far from stable ! ( i dosed something like 6 ppm NO3 3times per week) ….

 

[Koan]

The leaves from the previous 2 weeks begin to be attacked by algae, some tip stunting etc

Two weeks is a short period of time

If i'm understanding you correctly, you have just made a large nutrient change from EI level to 10% nitrate for instance. All of the plants that were grown while you were dosing at a high dose are in the process of reconfiguring internally for the lower dose.

Those old leaves are going to attract algae because those leaves are not configured for the new fertilizer level. And it will take a while for a new leaves to be produced that are built from the inside optimized to your new fertilizer level.

 

[Mitelog]

No Koan , my previous NO3 level was fluctuating between 8 and 14 ppm during the week.

I talk about my older tank that i had 7 or 8 years ago, it’s in this one that i used EI

Talking about that, i think i will try EI the same style i used it in my old tank ( 3 Times per week) as every thing i have tried yet, in this new one have failed