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

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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.