The Custom Micro Mix Thread

[Koan]

stopped dosing the Yara tenso cocktail and started dosing Seachem Flourish last week, I am very curious how will things improve

What a great way to investigate this!

Unfortunately, because the two ions that you seem to have been accidentally overdosing are Mn2+ and Cu2+, both cations, there's a good chance the high CEC "cation exchange capacity" of your Aqua soil will have caused it to bind them up.

This means it can release those micros back into your tank, even after you discontinue overdosing

Have a look at this thread where another member @bradquade appears to have had a similar problem with toxicity, this time from excess Na+ sodium ions in his water supply

Journal Post in thread 'Recovering from disaster: My 120P journey.'

Feb 11, 2026

the substrate was new and absorbing whatever is bad in the tap water

Aquasoils are designed to have an high cation exchange capacity or CEC Sodium Na+ is a cation so it would your soil would bind up sodium over time, competing with potassium calcium and magnesium at the root-soil interface, as well as aggravating plant-specific specific sodium toxicity. This is one reason a hallmark of sodium toxicity is a lack of rooting

• Koan

• 

He has had much better success after replacing his substrate He has replaced with an inert soil, so the cost was much more reasonable than the new Aqua soil

 

[marekm]

Thanks a lot for the input Koan!
Thats very interesting, I would never know about something like CEC . I guess thats another negative of aquasoil, seems like the inert substrate is just better if you want to have maximum control over your water chemistry.
I will read bradquade"s journal for sure, the first thing that came to my mind is check the water quality report, unfortunately sodium levels are not listed there.

I think I will stick to large water changes for now and see how things progress, I have made an upgrade from 200L to 450L just 3 months ago so I am not feeling for a tank reset yet.

 

[Sepp0207]

Hi guys,
I have read that pinwholes in older leaves of Hygrophila can be a sign of overdosing mikros. I am dosing 25 ppm potassium per week with 50% waterchange. So potassium can’t be the reason for pinwholes. I am also adding 0,4 ppm fe DTPA with unchelated Mikros. Does someone know or can you guess which of the mikros could cause this pinwholes?

 

[Aclaar877]

Hi guys,
I have read that pinwholes in older leaves of Hygrophila can be a sign of overdosing mikros. I am dosing 25 ppm potassium per week with 50% waterchange. So potassium can’t be the reason for pinwholes. I am also adding 0,4 ppm fe DTPA with unchelated Mikros. Does someone know or can you guess which of the mikros could cause this pinwholes?

As far as my tank goes, zinc has caused me the most troubles. Years ago I saw immediate tox symptoms after routine Flourish use, dosing per the instructions. Flourish has a lot of zinc compared to other micros. More recently I kept zinc, boron and copper in individual bottles just to see if I could isolate the problems, and it seemed zinc doses never fixed anything, and the tank did better without it (with SafeTSorb substrate). I also transitioned to a low-tech "kill tank" this year (no CO2, no ferts, lower lighting) and some dormant AR Mini came back to life. Even with 100% RO water, I can never seem to dose the levels of zinc that other people manage to do.

 

[Burr740]

As far as my tank goes, zinc has caused me the most troubles. Years ago I saw immediate tox symptoms after routine Flourish use, dosing per the instructions. Flourish has a lot of zinc compared to other micros. More recently I kept zinc, boron and copper in individual bottles just to see if I could isolate the problems, and it seemed zinc doses never fixed anything, and the tank did better without it (with SafeTSorb substrate). I also transitioned to a low-tech "kill tank" this year (no CO2, no ferts, lower lighting) and some dormant AR Mini came back to life. Even with 100% RO water, I can never seem to dose the levels of zinc that other people manage to do.

Thats very interesting. Zn is one that I found severely low in csmb, it was one of the big fixes when I first started making the custom micros. I experimented with really high levels also back in the day. It was fairly benign as far as overdosing. I dont doubt your results at all. Most of us have seen issues that seem to only apply to us, I sure have! So Im just sharing what Ive observed

The only problem I ran into with too much Zn was it started to affect the availability or absorption of Fe. The sweet spot wound up being to have Zn roughly equal to Mn and B

Not enough Zn causes very short lengths between the nodes of many stem plants, namely Rotalas and Ludwigias. The sets of leaves come out stacked right on top of each other. That is the primary symptom of not enough Zn in a high energy stem tank

Hi guys,
I have read that pinwholes in older leaves of Hygrophila can be a sign of overdosing mikros. I am dosing 25 ppm potassium per week with 50% waterchange. So potassium can’t be the reason for pinwholes. I am also adding 0,4 ppm fe DTPA with unchelated Mikros. Does someone know or can you guess which of the mikros could cause this pinwholes?

Cu and Mn are the ones most likely to inhibit K uptake, per Mulders chart. Zn and K do not interact with each other

Ive never experimented to find what causes this faux K deficiency in Hygros that youre talking about, but its real for sure. If I were to try and isolate which one does it Id start with those two